Originally posted by brianl703:
At idle, that 130 amp altenator is capable of putting out 80 amps @ 13.5 volts or so (the output voltage will drop as the voltage regulator heats up, but never below about 13V).

It shouldn't be dropping as low as you are reporting. No way, no how. At 12.2V, you are discharging the battery. At 11.8V you are discharging it even more. Not good.

It's normal for the voltage to drop that low with all of the accessories on at idle in a 1988 Mustang GT with a 65-amp alternator[which, in fact, is why I replaced with a 130-amp alternator], but it is NOT normal for any Contour.

If I had to take a guess I'd say that one of the alternator diodes has gone bad. That usually causes diminished alternator output, with the possible side-effect of causing a battery drain when the engine is off.




Hey I said I was guessing!!!

"Fear is the little death." Muadib.