Electrical - Lights Flicker/Dim

[Oxide36]

The issue is all my lights flicker/dim. They don't completely turn off and on, but alternate between dim and bright very quickly (several times a second). This includes all the lights, headlights, fog lights, dash, brake lights and isn't very noticeable. Another peculiar thing is sometimes when I brake the radio will shut off for a second and come back on. This happens more frequently when the rear defroster is on. A few times, when a lot of things are on..AC, defroster, radio..the radio would not stay on, it would turn off and on so quick that no sound could be heard. Also, if I, say, adjust my electric seat, all the lights will dim while it's adjusting. I heard this could be a number of things.. voltage regulator, the whole alternator, or a ground issue seem to be the most common. My question is, where do you suggest starting? Should I get the alternator tested first to rule that out? If the alternator tests okay, then the voltage regulator is okay too then, right? How do I test the alternator? Do I need to remove it from the car and take it to Autozone? Or do they test it in the car? Lastly, where are the grounds that I should check? I have no idea about where to look.


Thanks for any help.


Edit (Resolved):

Hey guys. Thank you for all the replies. I believe I have resolved this issue - it was a really easy fix.

I checked the battery terminals and played with the connections. They were very tight and snug, but I noticed moving the black (-) wire, the trunk lights would flicker. I traced the black wire from the battery to the chassis which is only 1-2 inches away from the battery itself. I lifted up the trunk floor mat to gain access to the spare tire, removed the plastic trim piece, and saw where the black wire was bolted to the chassis. This connection was very loose. I tighten it up and played with the wire, and no flickering. My cooling fan recently crashed into my radiator and the radiator is leaking a bit, and the fan is obviously destroyed, so I can't extensively test it out, but I drove the car around for a few minutes (just until it hit operating temp) and didn't see a bit of flickering.

[flyfishvt]

the first place to start is use a meter to test the alternator output at the battery terminals while the engine is running. It should be a very steady output. If it bounces up and down then its most likely the voltage regulator. This can be replaced.

Your best bet is to take the alternator off and have it tested. Most parts stores can test it. In fact the Autoparts International store I go to has the testing equipment right on the counter.

[sunbrn]

Autozone will test it while it is in the car. They can put a load on the system while your engine is running and also check your battery.

[copcarguyp71]

I hate to sound stupid on this but before you get knee deep into the problem have you checked the battery connections? Also have you checked the battery voltage just sitting there with the car not running? Does ther car start OK? If all these check out then definitely have the charging system checked by the garage or parts store. Make sure they use a good analyzer type diagnostic and not just the old carbon pile type of unit...these don't really tell the whole story.

[Oxide36]

I hate to sound stupid on this but before you get knee deep into the problem have you checked the battery connections? Also have you checked the battery voltage just sitting there with the car not running? Does ther car start OK? If all these check out then definitely have the charging system checked by the garage or parts store. Make sure they use a good analyzer type diagnostic and not just the old carbon pile type of unit...these don't really tell the whole story.

I have not checked the battery connections. What would I be looking for..corrosion? I think they looked good. I had the battery tested a few months ago, I can't remember if I bought a new battery or if this one was still good, but the battery itself was ruled out as the culprit. I'll check out the battery connections when I can. The car has always started up great. No problems at all there. Does anybody know where these ground connections are to the chassis?

[flyfishvt]

Now I'm the one who feels dumb. I should have told you to check the battery connections first. just get a wrench and make sure they are nice and tight. It wouldn't hurt to take them off and clean them.

There are a lot of ground connections on these cars. The ones that are easiest to get to are the two in the engine bay. Just look for two bundles of brown wires. One is on the passenger strut tower. I believe the other is on the drivers side.

[Oxide36]

Hey guys. Thank you for all the replies. I believe I have resolved this issue - it was a really easy fix.

I checked the battery terminals and played with the connections. They were very tight and snug, but I noticed moving the black (-) wire, the trunk lights would flicker. I traced the black wire from the battery to the chassis which is only 1-2 inches away from the battery itself. I lifted up the trunk floor mat to gain access to the spare tire, removed the plastic trim piece, and saw where the black wire was bolted to the chassis. This connection was very loose. I tighten it up and played with the wire, and no flickering. My cooling fan recently crashed into my radiator and the radiator is leaking a bit, and the fan is obviously destroyed, so I can't extensively test it out, but I drove the car around for a few minutes (just until it hit operating temp) and didn't see a bit of flickering.