My 122 wagon has been pulling this odd trick: The amp light stays on dimly whenever the car is running, dim enough that when driving around in the daytime you cant even see that its on. However at night it becomes apparent that indeed the amp light is on and when I turn on my headlights, the amp light seems to get dimmer. I assumed that this meant that my voltage regulator was letting the generator overcharge the battery- but then two days ago, I started her up after sitting for 5 days and I noticed some starter hesitation. I drove into town, parked, and when I came back and tried to start it, the battery went dead before she would fire.
A jump start later I made it back to the house and put charger on it for a few hours. Then I started playing with a volt meter..... Im getting an even 10 volts out of the D+ terminal of the generator at idle and this reading does not change with RPM. Im getting about 7.5 Volts from the DF terminal increasing to about 8 or 9 volts at higher RPMs. Whats going on here? Might this also explain why a few months ago my old voltage regulator's generator side cooked and melted its terminals? I was getting a green spark between the contacts when they were closed which eventually cooked the contacts. I put a Bosch replacement in (identical) and it worked fine for about 3 days (no amp light at all) and then all of a sudden driving home--a bright amp light! I opened it up and the same thing was happening: The little contact (towards the front of the car where the D+ and DF leads connect) had melted (it looked like someone had dripped solder on it) I scraped the stuff off and the amp light then went out (most of the way) Am I correct in assuming that the lower voltage coming from the Generator is causing the electromagnet in the voltage regulator to not close all the way causing sparking and melting? What should I look for in the generator which might be giving me such low voltage readings? Help! :-)
Nate