weird light"flashing".

[heliman79]

this is going to sound strange, as im baffled too, but today my wifes 2000 ls sport's lights( interior, panel, head and tail)started "flashing", not dimming to the idle of the engine, almost seemed in unison with the ignition, accompanied by a slight whine, the engine also had a studder to it, not really what i would describe as a miss though. i was sure it was about to strand her on the interstate( ive had lots of issues with alts) so i was on stand by, but it made it home, well i shut it down, fired it back up it and the lights were solid and engine was smooth, checked all battery connections, etc, let it cool for 2 hrs, started it back up and the problem was back, shut it off and restart and its fine!! the alt was replaced 2 months ago, and battery is 4 months old. it fires right up, the battery light does not come on, could this be a coming regulator failure in the alt again?? im stumped! it does have the notorious v.c leak , which i got to significantly slow down but previous alt failures were abrupt and obvious.

[ES_97Sport]

Its not impossible that you got a 'bad' alternator. Given that almost all the rebuild parts are coming from China, it wouldn't surprise me. But, it kinda sounds like that may be the issue. Again.

I can tell you this for sure - it takes very little oil getting inside to fry an alternator.

Something to check that you didn't mention. Is the belt properly tensioned?

Edward

[heliman79]

well, had the alt checked and its all within range, so this leads me to start chasing grounds. any notorious ground issues(locations) i should check first.

[ES_97Sport]

Dec 26, 2014 12:54:24 GMT -5 heliman79 said:

well, had the alt checked and its all within range, so this leads me to start chasing grounds. any notorious ground issues(locations) i should check first.

Fun times, fun times .... Nothing I love more than chasing me some ground problems.

Ok. ...

First two - 'cause they're easiest - are the two on the top that run from the engine to the fire wall. These are braided ground straps. Almost certainly not the culprit but like I said, easy.

Next is the negative battery cable. It attaches at the block, frame, fender skirt and battery (in that order).

This is where I'd start seriously looking. The negative cable isn't a miracle of engineering. Not even Chinese engineering. I don't know if you want to try to salvage it or just replace it. If you have a lot of miles and the vehicle sees road salt and deicer, it may be simpler to just replace it. Deicer will eat that thing alive and leave you with something that isn't fit to try and salvage, so .... You'll have to pull the battery but the cable can be pulled with a socket set and (medium) long extension. Clean the terminals with a good wire brush as well as the contact points and spray them with brake cleaner when done to get rid of any oil film. (same process for the rest of the grounds)

There is another braided ground under the vehicle that goes from the t-case to the body. Its supposed to be on the passenger side. I don't think that's changed between '97 and '05. Usually its missing.

Those are the only external ones I can think of off the top of my head. Its also possible that something inside has loosened up, but unlikely. I'd start here since the external ones are the most likely to be missing/not working.

Edward