I have a 93 W250 that over the summer, the voltage regulator and AC parts of the PCM would cut out. I can live without the AC, and as long as it charges often enough to keep the battery up, so what if the idiot light comes on now and then?
Fast forward to 2 weeks ago. VR completely went out. I had the alternator checked out, even though it had bern rebuilt in the last year. I mentioned bypassing the computer and installing an external VR. He had an internal one specifically for bypassing Chrysler PCMs. He put it in, told me How to finish hooking it up, which includes finding field power with the ignition ON.
I had no power with the ignition ON. Traced it to the ASD Relay. Got a new relay, but it is a light duty unit from the local parts store. It didnt help. In fact, with my hand holding it, I can reach around the open door and turn the key ON. It clicks on, then right back off. I removed the relay, jumped the terminals with a wire, just to see if the alt would charge. It does.
Now, how do I go about determining why the new relays are going ka-flooey? I know, its likely junk parts, but what else is possible? Would it hurt anything to leave the jumper wire in place? I figured the relay was to keep load off the ignition switch. I may be in southeast MO, but I dont want to redneck hack it too much.
I have electrical diagrams in the FSM, but they dont do me a lot of good with my lack of training or experience in the field.
Daniel