Alternator?? Bad Connection?? Whacked out dash lights??
 

So I was on my way home Thursday evening and stuck in traffic when all of my dash warning lights start flashing randomly. I notice the voltmeter takes a dive and pegs out at the bottom. Dang! Well 3-4, minutes later "zip" all the warning lights, etc. go out and the voltmeter is working again, but now it's settled in around 10. When I rev it, it jumps up to the 13/14 briefly and then settles back down to 10. I tried to start it today and the battery is too low. So I'm thinking, #1 bad connection or possibly #2 alternator.

I rewired the rear dome light a few weeks ago as it was totally hosed (shorted out). I don't think it's related as it's run fine the last few weeks. I have to wrap up working on a friends 911 next weekened and then I'll take a peek at the alternator connections. Any advice is always appreciated.

Does the charge warning light come on? (ever)

The bulb is part of the exciter circuit for the alternator and must be replaced if bad.

Search on something like bulb alternator for more details, but that sounds like it.

Alternator maybe.....

Start with doing your connections cleaning first, if you haven't recently.

I thought the same about my alt, but turns out I gained 3-4 volts and the gauges never worked better......

--Russ

This is what happened to me recently. Upon pulling the alternator, found that the brushes were worn down.

Like someone suggested, take the alternator to a repair shop. They'll have it rebuilt and you back running.

Michael

Rebuilding your existing alternator is the way to go as already suggested.
A remanufactured Bosch is $157 so a rebuild should be about $50 to $90 depending on what needs doing.

Excellent advice. Not this coming weekend, but next I will pull it off and clean the connections. If I have it off anyway, I can have it checked out. The low voltage light never came on, the needle just took a dive.

I have this "poor connection" feeling, but that's what I thought about my friend's 911 (three weeks of rewiring and counting).

Thanks folks, will keep you posted.

well this is handy information..i recently replaced my alternator, but when i fired up the engine and measured the voltage back at the battery it was ~10.6V...turn it off, disconnect, and the battery reads 13+....well what i didnt know was that the lamp in the dash had a play..

See, i have the entire instument cluster out doing a rebuild on the speedometer and replacing the &**@^ edge connectors with D-shell pin connectors...had no idea the lamp in the cluster would impact the alternator..i looked at the circuit diagrams to see if having the cluster out would screw up something if i started the car, guess i missed that one...

Something to look forward to when I get the gauges in (although there will be bad news i'm afraid, some P.O. had removed several of the trouble lights, so it should be fun now that i've replaced them

Update
 

Pulled the alternator and it checked okay. Reinstalled it and now the warning/dash lights only come on for a flash (less than a second) when I turn the key to the run position. If I leave the key in the run position, the oil light and the master caution lights begin to flash. I'm getting a click from the center console, right side near the circut board/fuse box. It's not one of the solenoids in the array. Sounds like it is coming from behind the radio (I'll take it apart tomorrow).

Any ideas?

Sorry for being so dumb, but electrical systems have never been my strong point.

The remains of old alarm systems have been a pest in a couple of mine.

Some random ideas.

Make sure the battery is fully charged.

Clean the ground points. Dirty ground points can cause wacky behavior.