Again, I appeal to anyone who can give me some help with this darned truck! It's a 96. I had unhooked the batteries to do some welding on the truck. When I hooked them back up a week later,it arced across the positive battery terminal on the driver's side. I changed the positive battery cable ends, as they looked kind of poor shape. Now I have NO TACH, NO HEADLIGHTS, NO A/C, NO AIR INTAKE HEATER, and a radio that crackles when you turn the volume up at all! I have put in a new Engine Speed Sensor, New PCM, and even tried an external voltage regulator with no luck! I've tore the dash apart, and cannot find any melted wires there. All fuses are good, and the 120A fuse in the under hood fuse block was replaced too. I took the fuseable links off and seted them for resistance with a multi-meter and they were of too. Also took the alternator and batteries to town and had them checked too.

Does anyone have an under hood electrical diagram they could post, or a link to one? Any other ideas or suggestions? I need to get this thing going so I can drive it! If anyone can give me some idea of what to check next. Could the solenoids for the air heaters be bad? How can I check them? Any help or ideas would be GREATLY APPRECIATED!!!

 

need more info on truck? 4x4 auto tranny ??

 

4x4 5 speed. cruisce, air, NO power windows, lock or seat

 

You fried the PCM.

 

Like I said in the initial positing, I put a new (well actually used, but one that was tested and found to be good) PCM in it and it's doing the same thing. Maybe that one is shot too? Any quick way to test it?

 

Only way I know of to test the PCM is to swap it with a known good one.

Grid heater info> http://dodgeram.org/tech/dsl/trouble...niford_htr.htm

 

pcm doesn't control headlights, you can unhook air heaters, they can drain a battery very quick but still the headlights oughta work with a charged batt

 

Reach under the PDC and tug each of the large wires. When you find the one that is springy that is the fusible link that is blown.

 

check and clean all grounds

 

I checked the wires under the PDC. oesn't look like any fusable links to me. I have the two fuseable links that go to the air heater solenoids, and then two small ones that come off the positive side of the battery and go into the engine wiring harness. None of these appear soft or spongy, so I don;t think they are burnt. Here are some pics. Any suggestions?

Thanks

Mike

 

I unhooked the external voltage regulator I had installed, and now no charging. Obviously, the PCM or ESS doesn;t run the headlights. Could it be a wire from the alternaotr to the PCM? What is the chances of the original and this new PCM being bad?

 

Looking at your pics it looks like your battery terminals are very poor. The PCM I believe grounds to the drivers side battery clamp. All your problems could be ground related. The Radio is the first to notice a bad ground and will have interference with even any sort of poor ground. Ecm uses low voltage for it's sensors and again any grounding problem would interfere with the signal it receives. Does your truck have daytime running lights? If so the DRL module can be troublesome and may be affected by the same bad ground.

 

I cleaned all of the battery terminals, leads and grounds. Still no headlights, only about 8 volts on the gauge, no A/C, crackly radio,no air heaters, no cruise. This is starting to drive me NUTS!!!! I really hate to take it to a shop. It all started after I replaces my 5th gear nut. Unhooked the batteries for a week.After I hooked everything up, it didn't turn over very fast. I couldn't get it to start, but the air heaters did come on. I hooked a battery charger up to the drivers side battery, and that's when the trouble started. Now after everything has either been checked or replaced, I still can't figure it out.