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Dodge Repair/2004 ram 1500 intermittent power loss


I have a 2004 ram 1500 5.7 hemi, I have been experiencing some electrical issues with my truck.  I was driving one evening and all of a sudden my air bag light came on and dinged followed by wipers not working and my rear turn signals not blinking.  As of lately I've realized that the horn and high beams do not like to work when the truck acts up.  There isn't anything that seems to trigger these issues.  I've inspected the engine harness and grounds along with the fuses and relays, I've also replaced the multifunction switch.  Where do I go from here?

ANSWER: Hi Chad,
Let me check the wiring diagrams to see if I can find a common cause for these and then get back with an answer.

---------- FOLLOW-UP ----------

QUESTION: One further note, it did start having this issue when it was rain/snowing, however no matter the weather condition it continues to have these issues.  Thanks!

ANSWER: Hi Chad,
I checked the '04 manual for circuits of the systems which you identified as sharing the problem and found only two commonalities: 1. the digital data communication system (called the PCI bus connects to them) but also to many other systems that are not affected so I would doubt there is something wrong with that system overall AND  2. there is a common point where ground wires for these and other systems are attached to the body. It is identified a G104 and is located on the left/front corner of the engine compartment. Unfortunately the exact location is not shown on the figures but if you see location where a very large number of black wires converge to a place where all of them are held on the surface of a panel by nut or bolt then you might find corrosion and or a loose retaining bolt or both has caused these grounds for some of the items to be intermittent. If you don't find such a spot I will identify some other items that have grounds to that seam location and you can follow a black wire from the items I list to locate that ground. I don't find any commonality with the various fuses/switches/circuits other than the ground. The only other possibility would be the power supply to the instrument cluster which plays a central role but again it is not likely to be the cause of all of them.
I looked at the '06 Ram manual and that one does show the G104 to be located on the metal structural edge high up on the left side of the engine compartment just to the rear of where that panel connects to the metal structural part that goes across the engine compartment above the radiator. There are shown to be a large number of wires running along that same pathway because of many splice locations in the wire "harnesses", but the splices would not be very noticeable. The harnesses of course would be notable.
Thanks for the rating and nomination.

---------- FOLLOW-UP ----------

My truck had a check engine light pop up so I hooked the scan tool up and it identifies as a "lost comm with PCM".  I will check over those grounds again.  Thanks.

Hi Chad,
That would suggest that the first possibility is worth considering as the cause. Other than the "lost comm with PCM" was there a 4-digit fault code number?
I would expect that when you noticed the problems that you listed that also the functioning of the engine would be modified if communication with the PCM was lost.
I have the troubleshoot manual for the PCM for '04. If you can tell me whether you have a separate powertrain and transmission control module (each with 2 plugs) or instead a "new combined" module with 4 plugs that would help to identify which pages to send to you by email.
Tell me your email address, but don't use the @ symbol, rather use "at" or the address will be erased automatically.

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Roland Finston


Get a Free Fast answer to your repair question about a Chrysler/Dodge/Plymouth car, minivan, SUV, or truck. Problems with electronically controlled engines and transmissions as well as body wiring problems are my specialty. This free troubleshoot advice forum helps you diagnose faults, minimize repair costs or do-it-yourself.

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