Hello

The red lamp next to the voltage meter occasionally flashes on my '94 PAU. It is random, happens about once or a couple of times per day, and flashes very briefly - so fast I barely see it.

The voltage meter tends to fluctuate a bit as well. Most of the time it is above 12V as it should, but some times it slowly weaves between 12-14 and at times goes beneath 12V.

It got better when I installed new ignition coils and unit, but it still isn't quite well. The battery is only one year old.

What can cause this? Voltage regulator? Alternator?

Say - does the PAU have an internal voltage regulator, inside the alternator?

Because try as I may, I find no regulator in the humongous 1060-page Electrical Systems Manual, but there is a note inside the box that denotes the alternator. A "do not attempt repair" triangle with a "regulator" next to it.

But if that is the case, what are these?
http://www.autopart.com/partsout/199...ARKAVENUE/4884. htm

Yes, the regulator is internal. It is possible that the diodes are failing, which would allow an AC component into the electrical system. I would also check that all ground connections are in place and clean. If an erratic idle is contributing to the problem, you might also want to clean your throttle body, but be sure to use the proper cleaner, not the old carburetor cleaner. That stuff will remove the factory coating on your throttle body.


There was a time when we could replace the diodes, but nobody goes through the trouble anymore, and I don't know if it is even feasible now. That alternator is common on many GM cars and is easily available here. I realize that it may not be so easy there, but I do think that (if you have meters and can confirm the problem) your best bet is to just replace the alternator.

I just cleaned the MAF the other day. It was silly simple since it only had three small screws and a connector and sat on the front of the intake.

I guess I'll get a new alternator and see what happens.

Thanks!

no dont just throw money at it. diagnose.


1- get a multimeter and check batt voltage eith eng off.


2- then check voltage of car at idle with no loads on.


3- then check voltage at idle with all electrical loads on.


4- let SJ know the results.


p.s. use actual multimeter. do not rely on the dash guage for an accurate reading. theyre notorious for being wrong. close, but wrong.

Well, thanks for the advice but I decided to throw money at it anyway. $100 and a new alternator later, the car is well again.

Thing is that the problems were very erratic, so I figured the circuits inside the alternator had some problem that a multimeter would not show.