Alternators probs 87 cabriolet HELP!!!

I think you think correctly... at least if nothing is wrong in the OXS light department... ;)

If you unhook the wire from the alternator coming from the alt. light, it should go out. If it doesn't, there is either a short to ground, or other component (i.e. oil pressure control unit if it's like my 1984 schematic) that is drawing juice from that lead, and that is your problem. Of course, to disconnect that lead, you need to make up some heavy jumper leads so as to be able to have the other leads still connected. This would be my next step, AFTER assuring the grounds are good. Every time I've ever seen the alt light stay on with a known good alternator, it's always been lack of ground. Except, of course, for the typical lazy alternator syndrome. That's the one where, for some strange unknown reason to me, you can't get the light to go out and the alt to start charging until you rev the engine up pretty good. But that doesn't qualify at a good alternator : )

I'll try to get my later year book back to see what else might be different. I can send you a quick scan of schematic if looking at one helps your thinking ability any. It's not like the ecm is programmed to control the alternator voltage. If your alternator (including voltage reg) is good, you have a simple connection(s) problem in a simple charging system.

But if your battery's staying charged (been driving it the past week?) then there's always the famous fixall electical tape. Just cut a small peice, square and neat, and apply as you would to a blinking VCR clock! And how's that head gasket job coming along?

running,...everything

Just reviewing your original post...

2 alternators in a row that are bad off the shelf is NOT by any means impossible! It IS an internal thing for the alternator to become "self exciting", which is what causes current to stop flowing through the light in the dash. But a bench test should show the same problem.

are you talking about the wire that is connected via a female connector? that is the alt signal wire right? I was looking in my bentley last night and it was not much help... though i did find this thing called the voltage stabilizer that is on the instrument cluster... is it a possibility that IT is bad? I havent figured out what it does...

what head gasket job are you referring to? the one on my diesel that i blew last year? some guy said that he would help me replace that... but i have to figure out which head gasket i need first... i don't know what notches i am supposed to look at to tell :( do you know?

suggestions

I'm was picturing the 3 in 1 female spade plug (2 battery wires, 1 field wire). But, I'm thinking now that 87 doesn't have that type. If your looking at the correct diagram in your Bentley, it should tell you the wire color. Probably the Bentley has troubleshooting for your problem that is similiar to my advice? Haynes manuals always do... (NOT) ; ) The voltage stabilizer in the instrument cluster has nothing to do with it. That's for the voltage to the gauges...

Does Alldate have specific diagrams for that car? Everything I have access to (so far) is Golf and Jetta. Neither of which are A1 but appear more similar at alternator than Rabbit up to 84.

If you have air condition, that ties in there too, looking at my 89 Cabby. Can't find a diagram to match mine either. Looking at schematics that DON'T match, there are a number of areas that could be causing the problem... Oxs mileage counter, ac control, oil pressure control, inst cluster itself,...

I'm betting that unless you indicate your willingness to leave the car and pay shop time for whatever time it takes to fix ($$$), the next 10 or even

100 shops you visit will have no clue.

If you can send me correct diagrams, I could offer more advice. If battery is definitely charging, you may need to just ignore the lights (tape). ; )