gldrsh

Does anyone know the proper way to wire an external voltage regulator on a 92 Ram. My computer does not charge properly. I tried doing it a few different ways. I bent the tabs back on the field wires, hooked up the regulator,tried switching the wires and it would not charge. Any photos or a detailed explanation would be appreciated.

wannadiesel

Looked at this one yet?

http://wiki.dieseltruckresource.com/...r_92-93_models

Before you give up on the PCM, make sure that the crank sensor wiring is in good shape and the sensor gap is around 0.050". A little tight is better than a little wide. Also check the ASD relay on the fender. It is the front one. If the truck has A/C, you can swap the A/C relay (rear one) for the ASD to see if that fixes it.

clops79

did you check the crankshaft sensor that will cause it not to charge, any other gauges not working right?

gldrsh

the link to the wiring was very helpful. Though I don't know which wire has 12 volts or is a positive hot wire when the ignition is on. The fuse panel does not have an ignition fuse. Which color is the wire I need to connect to the voltage regulator?

gldrsh

I have hooked up the external regulator and it is not charging. All the wiring was done like the illustration and it does not charge. When I hook up the regular wiring through the computer it puts out 15.6 volts. I have a Mopar tach and it works properly. Others have sugested checking the gap on the crank position sensor, it is .024. Any sugestion would be appreciated. If you want to give me your e-mail address I will give you my phone number or I can call you if you give me yours. I don't know what I am doing wrong since others have hooked up the external regulator and it works. I live in southeast Michigan. If someone has done this I would like to look at your truck if I could, thanks.

wannadiesel

There's nothing wrong with the crank sensor since the tach works.

It sounds like you have a wiring problem. Check the harness wher it goes over the top of the brake booster.

gldrsh

I don't understand why it overcharges when hooked to the computer but does not charge at all when the external regulator is hooked up?

wannadiesel

I think you're doing something wrong when connecting the external regulator. Do you have the regulator screwed to the truck or is it just laying somewhere? It grounds through the case so it needs to be screwed to a good ground like the firewall or the fender.

I think the field control wire in the harness may be shorted to ground, causing your overcharge when connected to the PCM.

gldrsh

Thanks for the response. I have the regulator mounted to the firewall and I also ran a ground wire from the regulator to the alternator. I checked for a ground and it seems good. I used the old plug that came from a junk yard that plugs into the regulator. It seems like a snug fit and I checked with a test light for to confirm the wire is hot from the 12 volt ignition source and it is,at the alternator and the proper terminal of the plug. What I was going to do is cut the triangular plug off and use new female connectors inplace of the plug. I think I have it properly wire and am disappointed it didn't work. I appreciate your suggestion about trying to determine if a field wire in the harness is shorted to ground. Could it be either wire that could be shorted or just one? There is a green and blue wire. Thanks for your help.

wannadiesel

Field control is green, the PCM pulses ground to that wire to control charging voltage. The blue wire is 12 volts from the ASD relay to power the field.

If you have the green wire disconnected right now, check to see if it is providing ground all the time.

gldrsh

By checking to see if the green wire is grounded all the time do you mean putting a test light hooked to the positive terminal and touching it to the disconected green wire at the alternator but still hooked to the computer? I disconected the harness from the computer and the other end also disconected from the alternator,put an ohm meter at the harness green wire side and had no reading. I also did a continuity check of the green wire and it had continuity. I put new connections at the external voltage regulator side and it still does'nt charge. I feel I have the external regulator correctly wired. Why wont it charge. What are the chances of a bad new regulator? It's a Borg Warner cheap model made in China. I don't think it can be tested. Do I take it back and buy one from a different store? If the external regulator is suppose to work, I don't know why it is not working on my truck.

wannadiesel

That'd work.

It's possible that you have a bad regulator right out of the box. The alternator is obviously capable of charging since it overcharges when connected to the factory wiring.

918dodge

I tried this and for some reason I'm getting power on my green wire is that normal ?

j_martin

Not real sure what you mean by "this one".

The blue wire provides 12V to the field. The green wire is grounded by the PCM to varying degrees (that's what regulation means). If the alternator demand is not full output, it will be above ground but usually below 12V.

If it is at 12V, the regulator (PCM) or the wire to it is defective. If it is at ground and the blue is at 12V, the alternator is defective, specifically the brushes or field (rotor) winding. (all hooked up to the alternator)

918dodge

With my truck running I pull the plug and touch my test light to the green and blue connector and it shows that both have power on them