I am posting this for my friend (neighbor to my mother). He has a 24V Ram, '01 I think. Anyhow, he has been fighting the lock-unlock problem for a while. I had him pull the alternator fuse and try it. Same thing, no change. I also put a multi-meter on the alt to test for AC voltage and it was .013 volts at the highest. I suggested checking the trailer plug and possibly the brake light switch. He did say that if he cleaned the battery terminals and reset the APPS it might be good for two months or two days. What else should he check?

I am posting this for my friend (neighbor to my mother). He has a 24V Ram, '01 I think. Anyhow, he has been fighting the lock-unlock problem for a while. I had him pull the alternator fuse and try it. Same thing, no change. I also put a multi-meter on the alt to test for AC voltage and it was .013 volts at the highest. I suggested checking the trailer plug and possibly the brake light switch. He did say that if he cleaned the battery terminals and reset the APPS it might be good for two months or two days. What else should he check?

Had the same thing happen. Turned out to be a bad ground cable at the battery.  I cleaned and applied dielectric grease to all the ground connections.  Then it came back.  When through the same procedure but couldn't find bad ground.  This time I took the infamous black cable with brown tracer that runs to passenger side ground and I rerouted it.  I pulled it out ran it across the radiator then around the back of the passenger side battery.  So far I haven't had the problem since.

Can I use a non digital VOM to detect the small AC noise from the alternator? I'll start cleaning electrical connections.

Would the main negative cable on the right side rubbing on the metal elbow between turbo and intercool potentially be a problem?

Yes, an analog meter would work if you can set it low enough. You will need to be able to detect less than one tenth of a volt AC for it to work.

 

I have heard that the rubbing could cause issues, but can't say for certain. If it is rubbing through the insulation you would need to repair it anyhow.