1993 Charging Problem

[temanski]

I have a 1993 Grand Voyager.. recently the charging indicator stated to fluctuate (down).. I realized quickly that there had to be a charging problem, as I drove, I could tell the wipers and other components were not at 100%.. so I shut them off and took it to a repair shop. They replaced the alternator and said it seemed to resolve the issue.. the next day, same thing, it goes dead as I pull into the shop. Then then replaced the control module that regulates the voltage. The gauge now goes incredibly high.. then down to zero a few minutes later, so at times it's overcharging, other times, it's not charging at all. Over the past week, they've replaced the alternator again, and tried two more modules.. still no luck. The garage say that they've repaired similar issues like this hundreds of times before, but this time, they just gave up and said.. "you can take it to someone else, but at this point, they give up.."! They've been really good about this, not charging for basically 10 hours of work.. with no results.. but The van runs great, great gas mileage and still looks good.. any suggestions?

[plymouthsrock]

The charging system is controlled by the PCM. The PCM gets its reference voltage via the ASD relay, which I believe is on the driver's side inner fender. It must get the correct reading to control the field current. I believe there have been others with ASD problems, is this the "module" that was replaced? Otherwise, all connections between the ASD relay, PCM, and alternator have to be checked.