I had a positive cable short against the fenderwell. Now my alternator won't charge, I replaced the alternator before remembering this site. The new alternator has battery voltage to the main terminal on the alt. The 2 rear posts show zero voltage. I have checked all the fuses and fuse links that I know of. All the gauges are working as they should, so just I believe that I fried the pcm. Is there a definitive test that I can do or do I just find a replacement pcm? Other options available? What about the adding an external regulator?

thanks for the help

 

Try swapping the front and center relays in the row of relays on the driver's fender. The front relay is the ASD relay, the center one is the A/C compressor relay. The ASD relay supplies power to the field.

 

I will give that a try, thanks.

 

What year truck?

 

I'm sorry it is a 92 350 4x4 with a/c

 

on my 92 there are 3 relays on the driver side inner fender, the front and center won't swap, the front and rear do, but it made no difference, I don't know if my a/C was working before or not, it doesn't engage compressor now, but that would not surprise me either, it is on my feed truck that I usually just drive with the windows down.

 

Btt

 

BTT any one with an idea? Did I fry the pcm?

 

I had a no charging issue on my 92 that was fixed by changing the ASD relay, thanks to Dave's input. I picked up the relay from Napa for $6, might be a cheap thing to try. Your AC relay could have been bad and your ASD fried when the short occured.

 

I will give that a try, a guy also told me to get a scanner to put on it, said if it showed rpms, it was the pcm, is this correct?

 

If you can get an RPM readout from the PCM then it's very unlikely for it to be bad.

Your problem as I understand it is that there is no power to the field when the engine is running, correct?

 

yes sir that is correct, everything else that was working is still working, I have battery voltage to the large bolt, but zero to the others.

 

Btt

 

It's gonna be a fusible link or ASD relay problem then.

 

all the fuse links were converted to fuses before I bought the truck, I have the ASD relay on order, we have to order everything here, there is a Dodge dealer 65 miles away, but have not heard good reports for service on the older trucks from them. If it wasn't for this website, I would be in the dark.