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Ask Wayne Crawford Your Own Question
Wayne Crawford
Wayne Crawford, Shop Owner
Category: Dodge
Satisfied Customers: 4017
Experience:  MO Safety/Emissions Certified on all makes and models with a strong electronics background aiding in electrical troubleshooting.
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Dodge Ram: 2003 Dodge Ram 1500 4x4 Laramie, 5.7L with tow package.

Customer Question

2003 Dodge Ram 1500 4x4 Laramie, 5.7L with tow package. Right rear trailer signal not working. I believe the relays are internal to the box and not replaceable. In my box, I can hear the relays, but the right one does not sound right to me. I have no brake or turn signal on my rear connector. I purchased a used replacement power module, but it had the same problem, so I suspect that it may be the signal going into the main power module, rather than the relays or the module itself. I'm looking for help to trouble shoot this problem, other than simply replacing the whole power box, which I already tried. I am a controls engineer and have no problem with schematics or mechanical, if that is helpful.
Submitted: 2 years ago.
Category: Dodge
Expert:  Wayne Crawford replied 2 years ago.
Hello. My name is ***** ***** I will be helping you today.Remove the Front Control Module and try grounding pin 34 of the Integrated Power Module , and check the voltage on the White/Pink wire at pin 7 of the C1 connector on the underside of the IPM. Let me know what you get. The pins should be marked at the corners of the connector faces.
Customer: replied 2 years ago.

Hi Wayne,

I just want to make sure I get this right. The Front Control Module is the module on the fender side of the main fuse box, which is the integrated power module, correct? If that is correct, can I just ground pin 34 to the chassis? If all of this is correct, I will try it some time this week and get back to you.

Thanks.

Jim

Expert:  Wayne Crawford replied 2 years ago.
Yes. The front control module is the module attached to the integrated power module (engine compartment fuse box) Let me know when you have that checked and I will figure out where to go from there based on your test results.
Customer: replied 2 years ago.

Nothing. Does the ignition have to be on? I have the FCM removed and pin 34 to ground. I have a pin clamp on the white with pink wire on C1(the connector toward the front of the vehicle on the Power module, to my meter with the common to the negative of the battery. See attached.Connections

Customer: replied 2 years ago.

I found a drawing of the power module. I was not on C1. Now I am, but same result. Meter shows nothing. Wondering if the ignition has to be on?

Connector layout

Customer: replied 2 years ago.

Tried it with the ignition on and no change. No voltage on the white/pink of C1 with pin 34 to ground on the FCM connector.

Expert:  Wayne Crawford replied 2 years ago.
With the key on and everything connected ground pin 34 of the FCM and with that grounded check pin 7 of the IPM for power. Sorry. I wasnt very clear there.
Customer: replied 2 years ago.

I have to remove the FCM to ground pin 34, so the FCM cannot be connected, correct?

If so, then I have no voltage on pin 7 of C1 with this configuration.

Customer: replied 2 years ago.

I don't know if it would be easier, I am fine either way, but I have about an hour to play with this so if calling me on my cell would be easier, that would be ok with me. (###) ###-####/p>

Again, either way is fine, just figured I'd offer in case that would be easier for you. Thanks.

Expert:  Wayne Crawford replied 2 years ago.
Yes you have to remove that. Verify fuse 47 in the IPM has power on both sides.
We can wrap it up in about two minutes. Verify power on 47. If there is power on both sides of the fuse then you need an IPM
Customer: replied 2 years ago.

Fuse 47 is good. So here is the part that has me troubled. The reason I am here is because I purchased a used IPM on ebay, installed it, and had the exact same issue.

I am thinking that the likelihood of the IPM that I bought having the same exact problem with everything else working fine is pretty slim?

I returned the IPM I bought, and I can buy another one and try it again, but it just seems odd to me that the one that I happened to buy had only the exact same problem. It had a new FCM as well...

Anything else to maybe check before I go and purchase another IPM?

Thanks.

Expert:  Wayne Crawford replied 2 years ago.
Thats it. If you got power on fuse 47 which feeds both hot pins of the relay and you are providing ground for the ground side of the relay then if the relay was working it would close the circuit between fuse 47 and the wire at pin 7 of c1.
Customer: replied 2 years ago.

With everything re-connected, I now have a lamp out blinking on the dash? Related? It was not there before.

I will check all the lights and see if anything is not working, but so far it looks like everything is...

I'll buy another IPM and give it a shot...

Expert:  Wayne Crawford replied 2 years ago.
I wouldnt think it would be related. Possibly something in the IPM caused by unhooking the FCM. Im not real sure. Unhook your battery cables and hold the metal ends together for a full 60 seconds to reset everything.If you get a good IPM and it doesnt work retest as I said then let me know your results.
Customer: replied 2 years ago.

I reset and the lamp out light is gone. I'll pick up another IPM and let you know what happens.

Thanks

Jim

Expert:  Wayne Crawford replied 2 years ago.
No problem. Let me know if you need anything further and please be sure to rate my service so I get credit for it. Thank you.
Customer: replied 2 years ago.

Hi Wayne,

I checked online for a used IPM and I can't seem to find the exact part number. For now, I have the right blinker jumped over to the trailer blinker wire. This works for the blinker, but I still do not have a right brake light on the trailer. I think rather than going with a new IPM from the dealer which will be way expensive, I'm going to try a 12V waterproof relay in the back. I'm going to run the right trailer signal to the common side of the contacts. I'll run the right brake light signal to the normally closed terminal. I'll connect the right blinker signal to the coil and to the normally open terminal. This should keep the two signals isolated and still allow them to work. The truck and trailer lights are all LEDs, so there should be no power draw issues. I realize this is not ideal, but any reason to think this would not work? I'm thinking for $12 versus about $300, its worth a shot...

Expert:  Wayne Crawford replied 2 years ago.
If youre going to run it off the tail light circuit use one of the modulators designed for that.. It may make your lamp out light come on. I guess if you are going that route you may want to just remove the bulb on the warning light and use the old fashioned method of checking your lights periodically. The only thing I could see going wrong is the added load possibly frying the IPM but then you wouldnt be any worse than you are now I suppose.Personally if I were going to do it I would probably dissect the IPM and figure out a way to put a new relay in there. I cant imagine it would be that difficult. Ive never done it yet but if I owned one and had this issue that is what I would do. I wouldnt do it for most customers just because from then on everything that went wrong with their truck they would blame on me. LOL