dodge ram 1500 no heat diagnosis.

howdy folks it's matthew your friendly neighborhood technician making a diagnostic video for you out of boise idaho um so what we're looking at is a 2002 dodge ram 1500 it's got a 4.7 liter v8 engine in it and the main complaint on it is that the heater quit working on it so sometimes heaters that don't blow hot anymore can be a little bit of a difficult diagnosis because there's quite a few things that that are involved with heaters working first of all let's talk about how does a heater actually provide heat to your vehicle okay so the way a heater works the the way it provides heat is via the heater core so the heater core is like a little mini radiator inside of your dashboard and there's a plastic or a metal door that in modern times today is ran by an electric motor alright so when you turn your switch here from hot to cold there is an electric door back inside of there that opens and closes okay now it either opens when you turn it to hot it opens the heater core or exposes the heater core and that is where you get your heat from or when you turn it to cold it closes the door to the heater core and that is where you get your cold air from to keep it simple okay so oftentimes it could be that the blend door actuator or the blend door motor for the heater core is not working correctly and so you're not exposing your heater core and so that is something that one would want to check all right and on this dodge you can look underneath here and now watch as i turn from hot to cold you will see that little arm in there moving watch okay so that's cold so that's the heater door closing and now that's hot and so that's the heater door open so we know that the actuator or the motor for the heater door works something else that i went ahead and did was [Music] i removed the face plate here and this vent and i stuck my camera my inspection camera i'll show you my inspection camera these inspection cameras when i was working on cars 20 years ago was not something that we had in our arsenal nowadays you can rent these inspection cameras i bought this one for fifty dollars but just to ensure that we weren't dealing with a blend door issue i went ahead and ran my inspection camera down inside of the vent found the blend door and saw that the blend door is properly opening opening and closing and exposing the heater core so i absolutely eliminated the blend door or the switch as the issue as to why we are not getting heat something i want to point out though is as i was doing that okay i removed the glove compartment and again let me see if i can get you up in there and i noticed something okay this truck has multiple blend doors okay i apologize for that i accidentally turned the video off so i had to edit it and put these videos together anyways you can look up inside of here and this is your defroster recirculatory blend door all right this truck is absolutely missing that blend door it's been broken and it is gone and let me see okay so see right here is the motor the actuator for that blend door that motor does not work and if you look up in here you can see where my finger is pointing right up in there where you see that white bit at the top right there okay that is the little arm for the blend door and that is broken somebody has been in here before and they removed that blend door obviously because it broke off and probably was flapping around down in there so more than likely what they did to get that out of there was they removed the fan and so they removed that blend door so this truck is missing the defroster recirculatory blend door and that's why this doesn't work at all so we do have an issue there but that's not why it doesn't blow hot another thing i noticed while diagnosing this vehicle is [Music] this fan only works on high so that's an indicator that the regulator which is right here that's an indicator that the regulator is no good and the fan is is beginning to go out but again that is not why the heater is not hot so we've pretty much eliminated the electronic factor the switch is fine the blend door is working all that other good stuff so what else could it be well oftentimes a heater not working properly is one of the first signs that the water pump is going out now let's look at our temperature here you can see that the truck is beginning to run a little warm and overheat now actual overheating would be if this temperature gauge were to get all the way to the red okay if you're in this area technically you're still safe but if you get to the red that's when damage occurs that's when the engine is running really hot these dodges they're not supposed to be over the mid mark they're either supposed to be right at the big mark or right before the mid mark so again we've already eliminated the electronic factor so that more than likely means we have a mechanical issue as to why the heater is not working and we can already see that it's running a little hot okay so remember what i told you about the heater core all right so how does the heater core heat up how does it get hot all that other stuff okay well the heater core and right here are your heater hoses okay they're right here i'll tell you right now there's no pressure they are they are hot but there's absolutely no pressure in those hoses okay so the fact that they're hot that tells me that coolant is flowing through there but the issue is is that there's not enough pressure for that coolant to properly flow through the heater core and heat the heater core up okay so the number one main culprit of that is a water pump okay so how is it that the water pump causes the heater core not to pressurize correctly well what it is is it's the bearings in the water pump are getting weak and so the impeller is not properly pushing the coolant through like it's supposed to it's not exactly causing the engine to overheat because coolant is is moving through the system but it's not moving through the system like it's supposed to and so that's going to be because the the bearings in the water pump and the impeller are not properly moving that coolant through so a new water pump and at the same time a thermostat is what it will take to get this heater to start blowing hot again another thing you can do to prove that it's it's a weak water pump is when you get in here give it the gas a little bit and if when you give it the gas you start feeling the heat get just a little bit hotter again for you again that that will tell you that yeah that heated core is not heating up like it's supposed to um oftentimes people will think that they have a bad heater core heater cores clogged heater cores yes yes they will clog and yes they will go bad but you will see other signs and symptoms with a heater core that's going bad you'll see coolant leaking onto your floorboard you'll also will be able to smell coolant if you have a leak and so we we don't have some of those issues here so again we go back to the water pump some of you might say well what about the thermostat well notice that after i give it the gas [Music] our temperature begins to come down a little bit okay that tells me that that the water that the thermostat is opening and it is working correctly and that now coolant is starting to move through the system but again we're still running a little hot and it will begin to run hot again leading back to the fact that the water pump is getting weak and showing signs of going out so the final diagnosis on this one to get the heater working we need to replace the water pump and the thermostat bleed the system out put new coolant in it and go from there so alrighty folks well i hope this video helps you to diagnose your heating and cooling issues let me know if you have any questions shoot them to me in the comments let's trade emails let's trade phone numbers i'd be more than happy to help you out thanks for coming and hanging out and watching my videos also thank you for supporting don't forget to like and subscribe this is matthew your friendly neighborhood technician signing off

Channel: Matt Shaughnessy

Views: 143,659

Keywords: #YouCut

Id: HyIao9Ah48Q

Length: 10min 38sec (638 seconds)

Published: Mon Jan 25 2021