Electrical Help

[mgould4]

I have a problem with the battery light flickering. I've been to two places that have both check the battery and alternator and said the charging system is fine. I know something must be wrong though. My base voltage is always strong, so it's not a battery problem. When I cold start the car, it starts well and I get great voltage and no battery flickering. I drive a bit and the second time i stop the car wihtout fail the battery light begins to flicker and the starts doing funky stuff. I've also noticed that when the light is on and I turn on an electrical device like the lights, it will momentarily go away. Then when i turn the lights off it comes back. It's really bizarre. Same thing with the turn signal, when the lights flash on, the battery light goes off and then when they flash off, it goes on in perfect cadence.

Usually at the end of my drive though it's on almost all the way (no longer flickering) and the idle has started acting up a little bit. Slight surges between 1000-1300.

BTW, the alternator is brand new (2 week old Bosch unit), which has tested perfect twice as still good.

Any ideas or help guys???? I've searched a lot but not found this particular scenario

Thanks

 

[luv2rallye]

Check all battery cable connections and grounds for cleanness and tightness. Might also (rare) be an intermittent generator relay or it's connector. If brake light also comes on check brake fluid level and handbrake switch adjustment.

 

[WeaselHack]

Check all battery cable connections and grounds for cleanness and tightness. Might also (rare) be an intermittent generator relay or it's connector. If brake light also comes on check brake fluid level and handbrake switch adjustment.

Agreed...Check your ground wires and battery terminals for corrosion.

 

[mgould4]

Ok so, I checked to the best of my ability the battery cables/terminals and grounds (although I don't know where they all are). I cleaned the battery cables and terminals, etc... used di-electric grease on the connections and tightened everything up really well. Problem is still there. The brake light does come on in concert with the battery light so tomorrow I'll go check the brake fluid level.

2 Quesitons, not sure how to check handbrake swith adjustment and don't know what an intermittent generator relay is. Can anyone explain?

Thanks

 

[mgould4]

Check all battery cable connections and grounds for cleanness and tightness. Might also (rare) be an intermittent generator relay or it's connector. If brake light also comes on check brake fluid level and handbrake switch adjustment.

BTW, i thought the brake light always came on when the battery light comes on, but as a result of an electrical problem, not a fluid level problem. Wouldn't a fluid issue only cause the brake light to come on?

Additionally, could it be that the battery cables themselves are bad? I guess I would need a multimeter to check that. Probably time to buy one.

Thanks again for your help

 

[luv2rallye]

BTW, i thought the brake light always came on when the battery light comes on, but as a result of an electrical problem, not a fluid level problem. Wouldn't a fluid issue only cause the brake light to come on?

Yes, sorry, you are correct. So it is an electrical problem then, not a fluid level or handbrake switch issue.

Additionally, could it be that the battery cables themselves are bad? I guess I would need a multimeter to check that.

It could be - try wiggling them with engine running to see if the light flickers. Also wiggle the alt. cable. It can still be the alt itself also. No auto store tests them properly (only do go/no go). You have to have it tested at a place that repairs them to have a full and proper test (test about 15 different things and can find intermittents).
In a rare case it can be a faulty generator relay (next to the turbo waste gate solenoid valve) - see posts 4 (pics) and 15 here:
http://www.dsmtuners.com/forums/showthread.php?t=237330&highlight=diode+resistor

 

[mgould4]

i'll check that relay and wiggle some stuff around. You are right about the alternator , a real shop will run many different tests and probably uses an oscilliscope. I might look up a shop and have them take a look

 

[Defiant]

BTW, the alternator is brand new (2 week old Bosch unit), which has tested perfect twice as still good.

Brand new, or rebuilt? Either way, it sounds faulty.