Chrysler Repair: 1989 chrysler lebaron convertable, chrysler lebaron, 1989 chrysler lebaron

Question
I just purchased a 1989 chrysler Lebaron convertable (2.5 LTR turbo, with an Automatic trans), I have already fixed many things, but the one that is killing me is the amp gauge will peg out every once in a while and cause a "check gauge", "check engine" light. I looked into replacing the voltage regulator, but was told it does not have a voltage regulator. I was also told it has a "single module engine controller" that regulates the voltage? I am pretty confused. I hope you might be able to shed some light on this...Please.
Thank you.
Mark Stover

Answer
Hi Mark,
You were told correctly that there is no separate voltage regulator, it is built into SMEC. The voltage is regulated by the field coil of the alternator being oscillated between 12V and ground at one end while the other end has 12V applied to it at all times. Thus the magnetic field will be oscillated so as to maintain the charging voltage at its regulated level. The field coil wires are connected as follows:
The dark blue wire should have 12V on it all the time that the ignition switch is in the start and the run position. And the dark green wire goes to pin 14 of the 14-way plug at the SMEC. I think the SMEC could be failing in its control function at pin 14 intermittantly OR the wire might have an intermittant short to ground somewhere in the pathway between the alternator and the pin 14. Whenever it grounds it will cause the alternator to run at full voltage output. I suppose too that there could be an intermittant short to ground of that wire internally in the alternator itself. So I would look for a short some where between the coil and the pin 14 to try and eliminate this and if you can't find it then maybe replace the alternator or the SMEC which ever is less expensive and see if that solves the problem. The wire passes thru a 6-wire black color disconnect plug behind the battery. Otherwise it is in the harnesses.
Roland
P.S. I am sorry to be so late in responding but the server for the Allexpert site was malfunctioning for the past 2 days and I couldn't interact with it successfully.