Alternators probs 87 cabriolet HELP!!!

Four bad alternators in a row? Or a problem in the car? I'm going to say that it's something in the car.

As always, check and clean battery connections and all ground wires. A friend had some very strange electrical problems in a Cabriolet that all came down to a broken ground.

You could have a wire shorting out somewhere, or it could be a relay. If you've noticed any abnormal clicking from the relay panel, that would be a great place to start. I had a fuel pump relay that was shorting out intermittently. When it was shorted it acted like a dead battery. I was driving once with it clicking on and off and most if not all of the dash lights were doing strange things. The dash lights aren't necessarily relay related, just that any short can have strange effects on the rest of the system.

You might be able to narrow it down by removing non-essential relays and fuses. Beyond that, it's get out the multi-meter and start testing.

Good luck!

I can clear up on mystery here. VW connected the OXS light to the battery light through a diode so that the OXS light always comes on when the battery light comes on (but not vice versa). Presumably this was done to implement a bulb test function on the OXS light.

As for your real problem, how old is the battery >

they are two totally seperate problems though, the first two alternators were BAD they would only charge at 2V.... maybe my car wore them out to where they could only charge at 2V? I don't know how that would happen, but the two alts were bad.... now the next two on a totally unrelated prob... were both changed in the same day to replace the last alt that was charging @2V... they were charging @ 14V, but there was NO amperage and they cause the battery and oxs light to come on... the other two alts that only charged @2V did NOT cause the battery or oxs light to come on and maintained the car at above 12V so I could drive the car like that. I cannot drive the car with no amperage bacuse when I am sitting at idle or god forbid I try and drive it at night the battery is going to go dead in a heartbeat.....

"VWGirl"

I will try that... but don't see how I could have gotten a bad ground by replacing an alternator... never have before...

Make sure there is water in all the battery compartments and there are no hair line cracks in it. Had a 95' GTi that did the exact same thing-come to find out one of the cells had a crack in it overworking and eventually killing 2 alternators.

cruspeed

alternator.

This was a test done at Autozone... go to a local Auto parts store and ask them to check your battery... this is what we did...

The Voltage on the car read 12V... when I took the alternator off the car and tested the alternator it had a maximum output of 2V... don't ask me how that works... I just know what I saw...

If the

I am still confused, and so is everyone else that has looked at this car :( I don't want to take it somewhere cause electrical pobs cost big bucks to fix and I am broke right now since I took a week unpaid vacation :(

So i checked the new new alternnator on the car today cause i was convinced that i just had bad battery... well... battery tested out good, got 85 amps on the new alt (90 amp alt) reg voltage was at like 15V, diode pattern was good... car seems to read 14V all the time now... so WTF is my battery/oxy sens light STILL ON????

Well, I have a short term fix that seems to help. I had my scirocco running at 12V with the car running and would cause the car to misfire. So, I took a thick gauge wire and put two car stereo o-ring type clamps attached to each side of the wire and put one connected to the alternator and the other end I grounded on frame of the car. This has upped my Voltage by 1 so it is now running at 13V which is sufficent for now. This quick fix really does help. Give it a try.

I tested the alt by pressing the "charging system test" button and tested the battery by pressing the "battery test button" using the same tester as i did before... same tester they have at all FLAPS I believe

what is it supposed to be regulated at? would this be why my battery light is on? and is this a prob with the alt or the car????

I am not really sure what you are talking about here or what the o ring type clamps are.... but I have 14V(seems to stay fairly constant now even with the car at idle with accessories on) ... I don't need more... I just need my battery light to go off!

Is that gonna fry my battery???

VWGirl schrieb:

Did you measure the 15V directly at the alternator? did you check if there is a noticeable voltage drop from alternator body to the ground post of the battery?

Ingo

Comments inserted below...

Rabbits just a tad ealier than yours had ground wires attached via the type of connector that is crimped onto the wire and has a hole in it (aka ring type in other post). One end attached to the small threaded end of one of the 4 bolts that hold the alternator housing together. You will need to find a nut to fit if you want to do an add on. The other end tpically under one of the bottom bracket bolts to engine block (much bigger bolt, needs bigger connector). You can add a wire to rule out poor connection through the mounts.

This kind of statement begs to be clarified with exactly what was used to measure this, and exactly how it was connected to exactly what. But see my comments under your other post...

Ok, I'm gonna make an assumption here. Assume of course that I cringe at assuming to use the word assume in any circumstance... lets assume that this "push the button" test equipment gets hooked directly to the alternator and the battery, but isolates the two. So now the alt is no longer connected to the car but is like on a bench and your car is only being used to spin it. Test would seem to indicate that the tester can make the alt charge, but doesn't mean you car can. And assuming the tester puts a real load on it and it was actually drawing an 85 amp load while reading 15V, that's sounds like a good alternator to me! Tester can also indicate the battery is good, but also still doesn't test the car. The test for the car is when the alt tests good and the battery tests good, but you still have a problem with the car. And if your problem is resistance in a circuit that doesn't belong there, i.e. a bad ground or other connection, you'll only get partial charging ability.

But if your car has 14V all the time AT THE BATTERY when running AND with lights, wipers, blower motor, AC, radiator fan running,...everything on... then you don't have a problem. Otherwise, 14 volts is not really up to where it should be. Perhaps your idiot light problem is because the mileage reached the kick-off amount to trigger the OXS light? Try resetting that. Otherwise, I refer back to my original response regarding wiring problems... or ground problem. But while you have everything on and running, and if you have a volt meter handy, it is a good time to check your grounds by looking for voltage across connections. It's an "ohms law" thing. With meter set to read small amount of voltage, probe between (-) post and ...(-) post connector, wire at connector, connector at other end, engine block, fender,... anywhere you can detect voltage between grounds indicates resistance. This is better than using the ohms scale to check for resistance. But it only works if things are turned on.

Also, if this car was a leased vehicle... some of the early contracts had a clause that basically stated if you failed to pay the electric bill part of your rental aggrement, they would come and shut your battery off.

: ) Hope your not too frustrated for a laugh...

they have the OXS light set up to go off at a certain mileage? didn't know they did that stuff way back when... and how would you fix it? I thought that the battery light turned the oxs light on, but the opposite was not true? in any case it seems like an odd coincidence that this would have happened without moving the car...

Don't think about it so much! Unless you reach the thinking part about if maybe it reached the trip mileage just as you go home (or whereever) and you didn't see the light come on. Or, it tripped but took a while for the switch to make contact (what? a bad electrical contact? vw? ; ) ). Or, murphy's law just throwing a wrench in your gears. Just find the button and reset it to rule it out (almost anyway, short of murphy). But your right. It doesn't really add up to your problem and no, there is no timer involved.

And CIS Lambda (not E), and CIS (no o2 sensor) and carburetted Rabbits had it built into the speedo itself. Had to pull the face around the speedo and reach in with a little wire hook and pull the lever. "Click". And then that didn't work cause that lever was for the egr light (anyone seen an egr on a cis rabbit?) and the OXS lever was the other one... harder to get onto... ; )