JacobK

iTrader: (10)

Hey guys i wasnt sure where to post this since so i figured i would post it here, It seems like when i turn my lights on at night, my the guage light pulsates like it seems the battery or alternator is going out? what is this, is it probably just my alternator or battery? Any help would be appreciated.. Thanks Alot
JacobK

DaddySS

Depends on what you consider flicker. If they dim and brighten slightly it is the normal cycling of the voltage regulator. There are few things you can do; number one - remove, clean thoroughly your battery terminals, clean and tighten your grounds - the main negative cable and the any others. The alternator can be serviced by a qualified repair facility that can fix the regulator "swings".

Other than that, if your voltage is 13.5 to 14.2 while running you're fine.

By the way, if your battery is more than 6 years old I recommend replacing it, they often last longer but they eventually leak, cause problems, terminals fall off from corrosion, etc. so why ask for trouble.

fil131

iTrader: (2)

I totally agree daddyss, you may want to grab a voltmeter and start getting readouts of voltages coming from the battery and alternator. If the battery is old try one from another car you have and see if the problem persists.

One obvious question I have to ask, this doesnt go away if you turn some accessories or stereo?

JacobK

iTrader: (10)

nope it doesnt go away..Someone told me its because i have an underdrive pulley, but that doesnt make sense does it?

zapp168

iTrader: (7)

My lights dim everytime my AIR pump cycles, it has done this since new. I had the dealer replace the pump just because it was a new car at the time. it did not solve problem, I just live with it. Car is 98 with 90,000 still has original alternator.

koolaid_kid

iTrader: (21)

No, I have been running an underdrive pulley for many years, and I have never seen this happen.

fil131

iTrader: (2)

Have you noticed any other issues tied into this pulsating/flickering? I mean performance wise, or is it just the headlights and dash lights?

zheiling

My dash lights, head lights, and interior lights flicker too. I was told to check all of the ground straps. Someone told me that the ones on the back of the heads is a place to check. I haven't had time but you could check yours.

Captain InsaneO

iTrader: (38)

My alternator with 30k miles on it made every single light on my car flicker, so I replaced it and it solved the problem. 30k miles!!! GM alternators must lick *****.

01'WS6

Ditto mine did the same thing. The diodes in the voltage regulators go bad and really start to cause problems once the altenator gets hot. I swapped alternators and it cured the problem.

Ls1Bait

Sounds like the alternator them. How old is the battery Jake?

Captain InsaneO

iTrader: (38)

One other thing.. my car's lights would pulsate quicker as the RPM's rose. If yours does that, I'd bet money that it is definitely the alternator.

redsscamaroboy

iTrader: (7)

I have the same pulsation in my lights .
I found a broken ground wire (the one behind the alt ,from the body to the block) i replaced it now waiting for exhaust pieces to get shipped so i can drive again.

Good luck.

Dave

SStheBest

iTrader: (2)

id start small first...i HAVE heard of underdrive pullies causin the alternator to not spin over as much as it should...hence the reason they over the alternator pulley ALONG w/ the underdrive pulley...my buddies SS is doin the same thing and its a 2000. He too has a pulley...look into replacin the alt pulley first and see if that changes it...if not then spend the money on the new alt

2001WS6Vert

We had a Dodge truck in the shop the other day and the problem was the underdrive pulley. We picked up appr. 1 volt switching it back to stock and it solved the pulsating lights issue.