GridHeater

this is a 2016 ram 3500 would have come in 6.7 liter diesel engine and it has the exact same problem that your stock truck has a suicidal grit heater the current that goes to these grid heaters is too high or well it's high enough to burn the bottom bolt that a grid heater off drop it into the engine and cause catastrophic failure Chrysler is well aware it is defect as a matter of fact in the FCA service manual they warn their service technicians that when they're troubleshooting an intake air heater problem that they should not long cycle the grid heaters because it could burn up the grid heater and cause catastrophic engine damage another thing they go on to say in the FCA service manual is that bolt right there they tell the technicians to check that for looseness we call it the jiggle test here on the forum and they tell their technicians that if that's loose at all even a little - immediately remove and replace the grid heater because that tells you that there could be a missing bolt or a partially burnt bolt inside the engine which will certainly blow the engine when it falls into a cylinder you the grid heater relay I call it a solenoid but the service manual refers to it as a relay there was a TSB issued on this component a few years back they have a nasty habit of failing in the on position that means that once you start your truck and the PCM sends an on command to the relay it stays on even after the on command has been dropped so you're driving around town all afternoon with the grid heater energized continuously it becomes a race between destroying your electrical system first or burning up the grid heater first and possibly blowing the engine the dealership flowchart Boise may be able to replace the grid heater and if you're real lucky they may even catch the fact that the grid heater relay is bad but the stress that the failed relay caused to the trucks entire electrical system will keep them guessing for a month if you ever have the dealership change a grid heater for you and then once you get your truck back you start noticing numerous weird electrical issues like strange behavior of your cruise control heated seats that keep turning themselves off and on or that turning on your fog lights turns off your air conditioning you'll know it's time to sell a truck if you bring it back to the dealer he's gonna keep it for a few days tell you we flashed the body control module and it's ready to be picked up but trust me it's not fixed it's just the beginning of the saga anyway let's get back to the original gist of this video one way to get around this problem on a stock truck that still has the grid here is simply to reduce the current that goes to the grid heater it's not that difficult what you need to do is just make a little voltage divider circuit here we simply put another resistor that the flashlights on right there in series with the grid heaters so what that does is it reduces the current on the grid heater in this case from about two hundred and twenty five amps down to about a hundred and fifty the grid heater still gets very hot but not white bolt burning hot and this way you can step away from that threshold where there's enough energy to burn that bolt off to do that the problem occurs that if the current goes under 200 amps on the grid heater circuit you're gonna throw a pea 2609 code and after two starts cycles actually on the third start cycle if the code is still there you're gonna set a check engine light on your dashboard and the reason that happens is because the intelligent battery sensor right there on your negative terminal on the driver's side looks at the voltage and the current of the truck all the time and it knows where it should be it controls when the alternator should charge more or less it looks at the grid heater - battery condition and one of the things it does is it looks for a significant drop in battery voltage when the grid heater cycles the grid heater is near a dead short on your battery so it drops the battery voltage from about a healthy 13 volts down to a very anemic 10 or 11 it looks for that drop so that it knows that the grid heater is healthy if it doesn't see that drop it sets a pea 2609 code which is a failure or impending doom for your grid heater circuit it knows that if that grid heater circuit doesn't show that drop it could be in the process of burning or already burnt off and it'll blow the engine so when Chrysler set up the programming for this they watch the pea 2609 closely now with the reduction in current on the stock grid heater I don't have to worry about burning a bolt off but I still get a pea 2609 code because the intelligent battery sensor is still looking for that 200 amps when the grid heater cycles so what I had to do is put a resistor a I guess you'd call it a dummy load right here and this dummy load adds in enough current on the battery to ground through a grid resistor I don't know if you can see it right in there and that develops the 200 amps between about I'm gonna use round numbers about a hundred amps on my stock grid heater and another hundred on this dummy load together that equals 200 amps so that the intelligent battery sensor is satisfied it's happy with that it sees that load I wanted to clarify some statements I made earlier about the intelligent battery sensor the intelligent battery sensor doesn't actually make any decisions or turn anything off and on all of doing is looking at the voltage and the current of the electrical system right at the battery and sending that information to the body control module from there it's put on the can bus and other systems in the vehicle use that information for whatever is necessary whether it's controlling the grid heater setting malfunction codes controlling the output of the alternator so the intelligent battery sensor itself is just generating this signal it's not actually making the decisions those decisions come from the particular module usually the powertrain control module this is a shot of the coils I used to develop my dummy load resistor so I can get the grid resistor circuit up to 200 amps and satisfy the body control module not to set a code I bought 2 frames each frame had two resistors in it so I had 4 separate coils to work with and I used the fresh car battery to clamp-on ammeter on a voltmeter and did my experiments to get the current on the trucks electrical system up to 200 amps while keeping the current on the actual grid heater down to about 125 so the grids get hot but not white-hot in the next clip the LCD voltmeter is reading the actual system voltage and not the synthetic voltage reading generated by the ECU also note that the red LED is connected to the actual grid heater and not the PCMs relay command so I can see what the grid heater is actually doing and not what the PCM thinks the grid heater is doing the LED is a must in case the grid heated relay was ever to fail in the on position first you'll notice the static battery voltage sitting at about 12 point 4 volts then the key is switched on and the grid heater preheat sucks that voltage down to about eleven point four volts at this point the LED turns on with the grid heater then the engine starts in the charging system is able to get the voltage up to about 12 volts finally after 30 seconds the grid heater turns off and the charging system is now able to get the voltage up to a proper fourteen point two volts you'll notice that the grid heater only cycled itself on once for 30 seconds and then was off for the duration of the run I did a test last winter and I had noticed that it's 30 seconds on six seconds off over and over again according to how cold it is this particular test was done the other day was in the mid-50s so obviously I got I was lucky to even get one cycle out of it one final issue needs to be covered on this the system I've built allows me to reduce the current on the internal grid heater to a safer more sane level and still keep the PCM happy so it never sets a P twenty six or nine code or puts an M il on a - it also lets me watch the grid heater cycle in real time via the LED and it gives me a method of ensuring that the grid heater relay never fails in the opposition without me knowing it however there's a better way to skin the cat I'm working on a small low energy solid-state module that will be placed on the output of the intelligent battery sensor and prevent a pea 2609 code without the need for a dummy load resistor at all once this new device is built you can completely disconnect your grid heater if you like and you still will not get a P 2609 code or set a check engine light the new device looks directly at the grid heater command from the powertrain control module and synthetically supplies a pseudo signal to the body control module in conjunction with what the body control module is expecting to see from the ISB at that specific time the concept is actually quite simple but get the values right will be a bit of a challenge it'll be a good winter project it'll be a lot smaller lighter safer and cheaper than what I'm doing now I'll see you then

Channel: Electro489

Views: 19,089

Rating: 4.8834953 out of 5

Keywords: Grid Heater, Cummins 6.7L

Id: dBPLZ3uf5ws

Length: 10min 58sec (658 seconds)

Published: Fri Oct 25 2019