A/C Clutch Does Not Engage-Diagnostic Fundamentals (full charge)

hey guys scanner Danner here I have my son Caleb with me behind the camera special thanks to Caleb special thanks to you guys for joining me today we're working on a 2008 Mazda 3 with an air conditioning complaint customer stated that he tried to add some refrigerant and made it worse that was the history we had I did do one thing off-camera and I did check my pressures already but I'm gonna start you guys from square one as I was teaching Caleb about air conditioning I'm gonna teach you guys too and this should be a good one so let's get started on the car all right so step one with air conditioning as you can see I have my safety glasses on we want to be safe in what we're doing step two I was telling Caleb off-camera there are two different size fittings for the low and the high sides of an AC system this is an r134a system it is not the newer refrigerant that they're using now which I don't know the number offhand but this is r134a these are the fittings unique to r134a every system has unique fittings so older systems had r12 refrigerant they were different fittings to killed they were not even the same so you could not connect an r12 car to an R one thirty-four a machine or recovery machine or gage set they're all different all right so r134a sizes this particular car has the fittings marked for us already we have a high side one here and we have our low side back here and if you don't know it's really not a big deal it's pretty straightforward as far as identification goes based on the size of them okay so this is an air line type fitting this pulls back and you clip it right over top and when I do that it should lock on but right now it is not depressing that valve inside you have to wind this down to depress the internal valve make sure your gauges are off up top right there closed connect your gauges up if your quick connects and then wind your fitting down that depresses the Schrader on both sides and now we can look at our gauges and see what we have and we're just over 90 psi same thing on the high side low and high side gauges and I've said this before in some of my other air conditioning videos that there is no low or high side of an AC system with the car off pressure equalizes and there's one pressure so just get a pressure reading I can say there's 90 on the low and 90 on the high but I don't have to talk like that with the car off there is 90 psi in this system all right so what do we know by that number one r134a refrigerant and our degree fahrenheit scale closely match each other every refrigerant has what's known as a pressure temperature relationship and the pressure temperature relationship for r134a is very very close to our Fahrenheit scale so it's about 90 degrees outside we should have about 90 psi in our system what this tells me to start with we have enough refrigerant in this system for the AC compressor to turn on that's where we are right now question scale remember your student - and people want to hear from you so we have enough pressure in this system for this AC AC clutch to turn on we'll get to that in a second I want to do just a little bit more of a lesson on the pressure temperature relationship for you guys just give me one second we're gonna use this water container for our example so a refrigerant is something that has a very very low boiling point so I believe r134a has around a minus 40 degree fahrenheit boiling point above minus 40 you get it into an atmospheric environment that's warmer and it will start to boil and change from a liquid to a gas so in a sealed chamber the only way that you could have if you picture this sealed chamber as our r134a refrigerant there's a mixture of liquid at the bottom vapor on the top you picture this container it has liquid refrigerant in there how can we have liquid refrigerant in an environment where we're at 90 degrees this should all boil off if this refrigerant boils at minus 40 degrees how could it possibly be a liquid look at a butane lighter it's the same thing you look at that liquid in the lighter it has a negative degree Fahrenheit boiling point - 20 - 30 degree Fahrenheit whatever butane is how can you have liquid the answer is pressure over top when we create pressure the top of a liquid we increase its boiling point so what happens in a sealed chamber like this container you pull this out into a warmer environment that liquid starts to boil off and it changes to pressure gas in the top and that gas pressure increases and that is what increases the boiling point of the liquid and then now we can have liquid in this environment and it's because of the 90 psi of pressure above its raised the boiling point to 90 degrees what happens when we change the temperature and make it a hundred degrees outside what happens to this chamber we boil more of the liquid more of the liquid turns into a gas we raise the presser more and now we have a hundred psi in here and we still have liquid left over okay all right so here's what we don't know let's say that this container represents a full system charge this is what we should have a mixture of liquid and gas 90 psi our pressure temperature relationship we would say is good that means we have at least some liquid refrigerant this is a representation of a full system charge mixture of both I'm gonna drink some of this thirsty I'm drinking all your water table you notice I left just a little bit of liquid in the bottom of this right we still have a container right now that my pressure and temperature relationship would still hold true so what I'm telling you guys is this first step does not tell us if our system is fully charged it only tells us that there is some liquid refrigerant still left in our system because our pressure and temperature will be matching the pressure temperature relationship will be holding true so I hope that analogy makes sense there's still some liquid left in there if I raise the temperature on this there's some liquid to that will boil off and it will raise the pressure how do you know when your system is low on charge so this initial test can identify a low tardes and here's why if I just get rid of the rest of the water okay no more liquid left what happens if I raise the pressure or temperature on this now let's say that let's back the temperature down some let's say we have 60 psi on my gauges in a 90 degree day what does that tell us that tells us there is no liquid refrigerant left just like this because what happens if this is let's say 60 psi of pressure in here no more liquid left what happens when I raise the temperature on this container 60 degrees 70 degrees 80 degrees 90 degrees the pressure doesn't come up any higher because there's no liquid left did I explain that better this time or better last time okay good that's what we wanted better this time I'll just tell you this the one last time if that was confusing for you guys the initial pressure test that we just did does not tell us without running the car does not tell us if our system is fully charged but it will tell us if our system is almost empty or empty right no pressure system is empty if if we were at 60 psi right now on a 90 degree day what we would say again we're low on towards we have a leak we know where we're going with this one being 90 psi we can't say it's fully charged but we can say there is at least some liquid in the system and our pressure temperature relationship is correct let's run the car now and see the state of our charge so that's what we're gonna do now all right guys so I'm inside the car starting it up blower position turn it on one of the speeds hitting the AC button green light lit AC should have turned on let's go under the hood look at our pressures as we were filming that part Pete informed us that this car was in a flood we some floods here a few weeks ago and when Pete first got the car the horn didn't work at all was making some weird noises it was the horn was actually underwater so we have some potential potential for flood issues here with this and this is kind of matching that from a standpoint you look at my gauges right now they haven't moved I'm still at 90 on the low still at 90 on the high this clutch has not has not turned on in fact it's a little bit lower now did you notice this a little bit lower less than 90 why is that because we're now in the shade it's not quite 90 degrees today and the system has cooled down so our pressure temperature relationship again in motion right there but here's the thing clutch did not engage difficult to see on this one see if I get you a shot you see the little knobs sticking out of the front of that pulley right there right where the square is around it that should be spinning with the AC compressor it's not the clutches the clutch is not engaged but our precious told us that our precious told us the clutch is not engaging at all and so the customer putting his own refrigerant in this basically what he did if he got any in at all is he over towards the system now back to our analogy picture my container with the liquid in it is there a way to tell it's over targed with our pressure temperature relationship the answer is no because there's a whole long whole big area where we can put more and more and more liquid in but you still have vapor area and your pressure temperature relationships gonna be fine so an over tardes cannot be identified by a static rest pressure test a fully charged system cannot be identified with a static rest pressure test a near empty and empty system can be identified what this test again tells us we have enough refrigerant this clutch should be turning on and so we have a lot of different ways and directions we can go now we can start checking the relay which we started to do off-camera because I wanted to get done quickly we were able to identify ahead my son helped me this is a faded cover but we were able to identify this or is it this one's that this one being the AC relay so we can go right to the relay and start doing some checks that's one method using simple tools to test slightly and whatever else another one because this is a newer vehicle it's computer controlled air conditioning is I can connect my scan to and see if we have any fault codes and I should also be able to see inputs so inputs with the scan tool we can verify things like the AC switch is the signal getting to the computer or and are there any full codes related to the system high and low side pressures potentially depending on the design and if those inputs are available so really scan tool is not a bad way to go some of you may not have a high end scan tool that can communicate with and get air conditioning information and so this next part won't be helpful to you but we will certainly be doing some relay techs in here so keep watching we'll get to this relay on this car I'm going scan tool next just to see if we have any fault codes alright so you see it's a 2008 Mazda 3 2.3 liter engine for those of you following a long one to fix your car I'm going to do a full system code scan on this I have no engine codes there are no codes in any of any of the systems doesn't mean we're done with the scanner go to my air conditioning system I got a note column here with my AC system that's not good no communication it didn't give me that see the thing about this I don't know enough about this system does it use a separate AC amplifier that's on a a can Network and these all talk to each other that's what it's maybe looking like oh cool we got some AC signals let's let's go inside the car we'll come back to that note column here in a second if you look at and this will be for you - Caleb I want you to be able to see this see the air conditioner request signal says on see that that data paid right there says on watch that same data pad will do this AC cycling switch - let's see what else refrigerant pressure switch module hit this button that should have set off air conditioning request signal still says on now you would want to make sure you're not in defrost because some of these modes like on Ford's if you're in any of the defrost positions it'll automatically have the air conditioning on so even though that stayed on when I turn that off I might still be in air-conditioning mode because this is still a blend here let's go to floor yeah it's staying on that's not good AC compressor cycling switch says on - it shouldn't yeah but that was the blower I don't like that this should be changing on and off with this all right notes for the back of our mind right now and on the reaction of that I want to come back to this for a second this no calm that we have with our heating ventilating and air conditioning system must be on engine off or running no communication right if that's on a network we should have communication errors and I'm not getting any of those and so what I've found on some of these systems so it's not even listed here so there's no codes in any of our systems and the fact that I have a no comm on the HVAC module and that it's not listed here tells me that it's probably not available on this car and this is a scan tool thing as far as the nocon goes because if it was actually part of a network we would have failures in these other modules that would say no communication with the HVAC control unit we don't have that so our no comm on the scan tool was because that feature is not available on this car that's that's my guess that's my guess so scan tools not helping us we're getting away from the scan tool now really for the rest of this we're gonna do some real a checks underneath I'm gonna stop this scan tool recording see my safety glasses have now been taken off not messing around with the refrigerant in the gauges anymore so my glasses are off some of you were gonna be like took your glasses off yeah so all right so I'm using a tool here from AES you have this you'll find this on my tool page on my website links for this guy you don't need this tool you can do relay checks without it but since I own this tool I won't do relay checks without it it's just that awesome so what I'm doing taking the AC clutch relay out matching it up to my tool plug in this guy in plug it into the back of the tool can't get it wrong and what we know right away see the LED light on that means the computer is controlling this relay so the LED light this is control side right and that clutch should have been this might just be a faulty clutch because that tells me this relay was energized in fact see if we can hear it click yeah hey listen yeah so that is telling me again that red light is telling me the control side is energized and that this is just simply most likely a clutch issue tell me if that light goes out when I hit my AC button Caleb is this still on all right so wait what you missed caleb is when I hit the AC button inside it turned the LED light off but never turn the control side of the relay off yeah it was the blower switch again which is the same thing the scan tool showed us reacted the same way so in other words the AC request signal stayed on until I turn the blower switch off I'm not worried about that I don't care that there's an issue with that because here's the thing the relays being energized we should have power to my clutch my AC compressor should be turning on okay so now I'm not worried about control side anymore control side of the relay would be the computers turning the relay on is saying to the clutch turn on so that means I don't care about any of my inputs we have an output problem from the relay load side contacts right here to the clutch down there we have a load side contact we have a load side issue so this tool there's no relay in here anymore I can actually take the load side and I can turn it on nothing happened in this light I think this light should actually be lit right now I still have to get familiar with this tool there's things that this tool can show me without my test light that I might be misquoting here I think we might be missing power to this find out with my test line power to the load side so we're missing load side power I think think tell you in a second one of these two should be hot okay there is there's my load side feed this one goes to the clutch right there is my switch clutch is not turning on okay and the other thing with this this is telling me there's an open if this I'm pretty sure that this bulb is wired for the load side contact that if the circuit is intact it'll find a ground through the winding of the clutch and that light should be lit on the load side now and it's pretty sure there's at the continuity to the continuity yes yeah we've done this like with fuel pump circuits I apologize I there's certain aspects of this light on the load side that I have questions on doesn't change how I'm going to approach the diagnosis here's the thing we got good load side power load the circuit switches on power did not disappear right that's still good this is the load side feed to the clutch so it's basically taking this red and attaching it to the green switch off light is off switch on light is on that clutch should be turning on it is not we need to get a measurement down there but there's another thing that we can do and that's where this light comes in here I believe but if I take my test light to battery positive when you get to the battery so test lights of battery positives what we're doing now notice my light lights when I find a ground on a good clutch circuit this should be lit just like a fuel pump calif picks her power going into here going down to the clutch through the windings of the magnetic clutch to ground it should be lighting my test line what's this tell me we have an open between here and the clutch most likely we got a faulty clutch what we need to do is a measurement down there to see if there so to see if there's power down there so when I flip this to power and send them and switch my test light back to ground the last test we need to do and then we're done is on this green circuit which is the the load side feed down to that clutch when I switch that to power I should have power down there and ground check my ground if they're good we're done we need a clutch the last part of this is we got to get underneath this car I can't get to it from the top and there's no power down there if there's no power down there then we have an issue in this box or in the harness and I'm not worried about the AC reaction inside on this car I don't care that the switch inside reacted to where the clutch was running you know that the circuit was active all the time I don't care what I'm trying to fix is get that clutch engaged I'm not worried about that input anomaly I am not doesn't help us at all some cars they will have that clutch circuit activated when you don't even have the button push for dehumidification some cars will turn the AC clutch on to stabilize the idle speed so there's there's variables with cars and without reading description and operation on this system I'm not gonna panic about the blower switch is the only way I can shut the magnetic Clutts off don't care here's the point the clutch isn't turning on right at all our issues on the load side we got to get to that I don't know if I can let me shut this car off the rest of our text we really can do with the engine off because that's the beauty of this tool is I'm just using this the circuit itself which is active all the time this is a hot all the time circuit and I can just flip the switch and do the rest of my checks now so we need to check that power down here can I get to it is the quest now that we got this car super hot that part was under water Caleb see if you can get a get a shot of this control arm down here straight down there that whole bottom metal bracket you can see muddled over it yeah and that's down in that area is where this AC compressor is jack and jack stands pull this wheel off I'm on a hill this is front wheel drive what happens when I take the front wheel off the ground the transmission Park pin is now up in the air if both wheels come off and now the car can roll bad stuff pull the e brake on which I did off camera also off camera I threw the transmission in neutral to check to make sure that my e brake actually holds this car in its position and it does so am i safe to lift this front wheel now or my back wheels holding and we don't want to trust just pulling the brake on and saying yeah we're good so here would be this scenario you're broken down on the side of the road flat tire you need to change that front tire you're on a slope you're on a hill people get killed all the time with this kind of thing pull the e brake make sure it holds throw it in neutral make sure the e brake is what's holding now go ahead and jacked out front wheel off the ground if it's a front drive if it's rear drive then you got to change up what you're doing that was more of a lesson for my son some of you will appreciate it Caleb you have any questions on that does that make sense real quickshot for everyone Jack Stan we're being safe granted we're in a gravel parking lot that's not ideal and I'm not putting my legs under this rotor just in case we also have the e brake on and we are safe with what we're doing so just trying to gain access to this AC clutch you know I probably could get to the wiring to it from the top but you guys would never be able to see what I'm doing so this is more for Caleb to be able to see and for you guys to be able to see that's cool I've never seen a design like this so one of the things that I did not consider when we were talking is this has a separate belt for the AC so here's my crank pulley here's my AC clutch and it uses a separate belt so one of the things that I didn't consider because I saw the serpentine belt spinning at the top I just assumed that was on the same drive belt remember we just did that alternator job in the driveway Caleb where we were missing a belt well we could have had the same problem although our test with the test light would have passed the battery test the battery positive it would have read through the clutch to ground so that told us it wasn't a belt but just something to consider is like this has a separate belt here's your clutch wire and so what I'm saying is if it was just a belt that was off the test light would have lit when connected the battery positive because it would have found a ground through the power wire in through the coil through the coil ground that would have lit the test light so that test told us we had a clutch issue but as I'm in here now I see there is a separate belt so that's that's pretty cool that they use a setup like this the wiring for that wraps around and it comes out that's what I thought I thought it was this wire and I can access that from the top just I bought one more thing here see where the clutch ground clutch gets its ground there's a connector right here back of the compressor can't see a ground location so this clutch end this is getting changed anyway and I'm using a my fills fills electrical probe freakin love this total man it's got a little better nails on the end of it right there so I'm gonna hook the compressor wire right right at the clutch itself move this insulation back this is all going to get changed with the clutch it doesn't matter exactly and if it if it ends up being no power here then I can just fix this with some liquid tape not a problem and it leaves such small holes it's just going to be my easiest way to do this for where we are right now so we're clear you see my test light so my switch off switch on I'm sending power down there right now we'll extend this over I'll reach up let's get to a ground check my test light good we're lit then I'm gonna touch the end of my my fills electrical probe that's lit yeah I'll see you have power today yep say you need a new needs a clutch I'm gonna reach up and flip the switch off flip the switch on flip the switch off flip the switch off so my wiring is good from up there all the way down to here switching my setup now back to battery positive when my test light finds a ground it's gonna light okay that should be lighting right now through the clutch itself so some of you are like quiet give me one second this will be my lesson so the AC clutch all it is a mag coils of wire makes a magnetic field electromagnet has a ground on one end and then this would come up to my relay okay I'm just draw the load side now what I'm doing is I'm taking what we did two things the last test that we just showed you I put a test light right here and I connected that test light to ground and I flipped the switch on my tool flip the switch I close the switch send power this way light lit how's my circuit from the relay box out to the clutch it's good no problem no opens right floods not an issue now the flood could have damaged the clutch we have to worry about this ground here's the thing it's not there's no ground wire so the ground is on the housing itself yet of the compressor there's no test for that I can I can sue my kids well I can test the compressor housing we can do that in fact here but before I go any further I'm gonna do that right now and what we're gonna do is we're gonna load this circuit I'm gonna go back to ground with my test light we'll come back to the power explanation here in a second the open circuit explanation so right now if I flip my switch I'm sending power down there we're gonna go confirm it again all right okay how do you test a clutch ground is first you load the circuit is the circuit loaded right now is my test light lighting on my tool yes circuits loaded all you need to do touch the housing if the ground was bad my test light would light on the ground of the housing it would like because it's open and if there is no ground there's no voltage drop and so it would actually light on the housing I refer you guys I have a bat a couple of bad block ground videos where a faulty starter and where the car wasn't cranking and I could make my test light light on the engine block yeah I'm gonna make you watch it Caleb so it's it's that simple with no ground wire on this if my housing is so if this clutch it does based on what I'm seeing it grounds on the housing of the compressor itself that would mean the compressor doesn't have a ground right if the ground was bad that means the compressor itself doesn't have a ground and if the compressor doesn't have the ground so we send power in the coil and then it goes through and then goes into the ground of the housing and if the housing isn't grounded the housing just becomes an extension of the winding and so it will light on the housing this is my ground test the fact that my test light is not lighting on the housing says I do not have a ground problem okay okay and then we'll back that up with some time stamps in some other videos with bad block grounds and how you can have a housing light a test light okay just to reiterate that where's this ground it's it's on the housing of the compressor okay and so there's what's the ground of the housing of the compressor ground to it grounds to the block so I realistically we could have a mounting point problem between the housing and the block so we're sending voltage in goes through the coil goes into the ground and fills the housing with 12 volts because there's no ground to the block so when you touch your test light on there to ground it would light telling you you have a bad block connection ground problem not our issue at all all right final part we connected our tool let's let's redraw this clutch ground here's our tool switch is open I now am connecting my test light to battery positive and what I'm looking for in this test is I wanted to see my test light travel through go through the winding of the coil into ground it should have lit my light most compressor clutch coils will draw to 2 to 4 amps somewhere in that range my test light I'm having trouble with my pen my test light only draws about 200 milliamps no problem no problem lighting that test light through the clutch coil circuit it won't be as good of a ground as a straight ground but 2 to 4 amps that's a real low ohm circuit that light should be bright ok so when we did that test that told us what open in the wire open in the Clutts coil or open ground we check which 2 did we check yes we take very good Caleb we check the ground we check the wire whereas our open clutch coil done I hope that makes sense guys I'm not sticking around for the replacement of this clutch you guys that are following along we get a lot of requests for AC videos AC repair type videos this would be one you could say hi to Lenny here behind my right shoulder he's in the background and then he's a longtime friend but guys please follow these procedures these are standard practice this is another faulty clutch on this car and again I apologize I'm not gonna be here for the replacement of this I don't know if it's gonna get a whole compressor or if it if the clutch is available separate my friend Pete Latour ATLA tours Auto is going to handle that part I've shown enough to troubleshoot this thing again we are not worried about the input side of this the input size irrelevant as far as the reaction of the blower switch and the AC button I don't care we have enough information here that this is absolutely a faulty or open clutch coil guys thank you very much for joining me special thanks again to Caleb Danner cameraman Caleb behind the scenes and again for more information on this stuff you want more training go to my website at scanner Danner comm and join my classes online scanner Dan or premium for 11 bucks a month you cannot beat the type of training that I'm providing on that channel right now there's 350 videos 200 of them being classroom type lectures where I'm teaching fundamentals and principles and we start applying all this stuff I look forward to hearing your comments you guys are on the fence about joining scanner Dan or premium I have a special request for you scanner Dan or premium members please put some comments in this video about what that channel scanner Dan or premium is doing for you guys because these other people need to hear it thank you guys I'll see you next time

Channel: ScannerDanner

Views: 469,838

Keywords: engine performance diagnostics, technician training, auto technician training, rosedale tech, auto repair, ASE L1, how-to, DIY auto repair, A/C clutch, no A/C, warm air, refrigerant charge, testing an AC system, manifold gauges, no power to AC clutch, AC clutch test

Id: oUAdikdm-v8

Length: 38min 56sec (2336 seconds)

Published: Tue Aug 13 2019