'03 Ram 1500 Trailer Wiring Electrical Gremlins

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Rambling

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2003
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Magnum 4.7
Hey guys, need some help here. I've researched online for this problem and even tried to troubleshoot it myself, but no luck. The problem I'm having is I don't have power for my left turn/brake light at my 7-way factory trailer plug in on my '03 Ram 1500 QC. I have an adaptor that plugs into the 7-way that coverts it to 6 or 4 pin. This adaptor also has little lights on it that indicate that the left turn/right turn, brake, and running lights are working correctly. When I plugged it in yesterday it was indicating I had no power to the left turn/brake lights at my 7-way plug in. I checked the wiring at the back where it plugs in and all seems fine.

I then removed my adaptor and confirmed the 7-way trailer plug was not getting power to that specific pin using my test light. The right turn/brake works, as well as the running lights. But no left turn/brake light. All fuses for the trailer 7-way plug are ok, and not blown. I even tested the left turn/brake fuse for the 7-way trailer plug at the fuse block (#46), using my test light and it showed power to both test points on the fuse. And I also hear the relay going when the left blinker is on. So what I'd like to know is what gives..? I've tried to locate the problem but I don't know where to go from here. I read that the relays can be the problem. But from what I understand they seem to be integrated into the IPM, (Integrated Power Module). So if that is the issue, from what I've read you need to replace the whole IPM. Which I'd really like to avoid, cause I've heard they aren't cheap to replace. So if anyone can offer me any insight on what to do or try that would be great.
 
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Rambling

Rambling

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Nobody have any insight on this..? Any help would be greatly appreciated.
 

derekp

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My dad had something similar happen on his ford. It was all integrated together and was like $800 to replace. So what I did was I tapped into the tail light wires and ran it to the hitch plug. You just have to find out which one is the correct wire for turn/brake. Does the same thing just uses a different route to get there. I can't really tell what the problem is on your truck without being there myself but it sounds like you're on the right track. If all else fails you could try that.
 

RonJon '06

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I had a similar problem with my 06, TIPM was bad. They sell an actual harness that plugs into the truck tail lights then down to the 7pin, 50 bucks but cheaper than buying a new TIPM.
 
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Rambling

Rambling

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I agree with that RonJon. So I think I'll probably end up going that route if I can't figure it out. Cheaper then buying a new IPM as you stated. Do you know where I could buy this harness for the 7pin, (Link)..?
 
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Rambling

Rambling

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Just thought I'd give everyone a little update here. After doing some more diagnosis, and getting my mechanic to double check my theory. It is indeed the left trailer turn/brake relay that was bad. The left/right turn relays both make two distinctively different sounds when their on. Plus my mechanic actually had a used fuse box laying around that was the same as mine. So he swapped my fuse box out for his and my trailer lights all worked. So I was right to suspect that based on the issues I was having and the the information I found out online.

Now, just to compare prices with everyone. A new replacement fuse box (IPM), would of cost me $950 from Dodge. Wow..!! And a used one was $440 with shipping. Ouch.
 
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