Rodzilla

Well I usually drive into work in the dark in my 2001, so I always have my headlights and foglights on. I have noticed that when driving down the interstate that my lights will dim for a second or two and them come back to normal brightness. I'm not hitting any electronics at the time when it happens. Anybody know what may be causing this? Do you think it's my battery or alternator starting to go?

Thanks,
Rodzilla

Patches

I have heard this complaint often from C5 owners and have experienced it myself but have never heard of a fix for the problem. Some have attributed it to a weak charging system and others to inadequate grounding. Interestingly, my underdrive pulley has not impacted, one way or the other, this "feature" in my C5.

I'd also be interested to hear if anyone has gotten to the bottom of this or gotten an explanation from GM.

srsjuju

happens to me all the time, been to the "experts" at Gm and they have no clue.

Sucks to be us.

vermjpv

Does it on my 01' vert also. Haven't heard it mentioned here before.

sxeC7

Interesting! All of you are '01 or newer. Might be worth doing a poll to find out how wide spread it is. I haven't seen it.

KODAK

All the time for me too. Anyone know what it is or how to fix it?

Hiteck

Mine does it too, 99 Coupe. I switched out the Delco battery with an Optima Red Top, but still get the dimming every now and then. I would have to say that it may not be typical to C5s, but many of them have this happen from time to time.

JPEK

I've a '97 Coupe and have consistently experienced dimming headlights while driving in the dark, but only when I hit my windows up or down.

My mechanic suggested trying a higher rated battery, but I've yet to do so.

Besides, I kind of like this feature when behind someone and wanting to get them to pass, rather than flicking the hi's

MrLeadFoot

Just so you know, my '00 Suburban does it, too. It's a GM trademark.

Wolfmanjohn

My '04 coupe, as well as my '00 Denali, do it. Seems to coincide with the A/C compressor clutch kicking in, as I also feel a slight lug most of the time it happens.

birch64

my 2000 c5 also does it.............

splash

I have had this problem before also, here is something you might want to check. If you still have the side mount battery post, over time the will work themselves loose and this will cause a lot of problems that may be overlooked. It my fill like it tight and snug but believe me just get a pair of pliars and make sure it is making a good contact. This is for both positve and negative post while your there make sure their isn't any corrosion build up and that your battery is not leaking. Good luck.

jdmvette

My car does that but -and here's the catch- only after you first start it and for the next few minutes. After that it does not happen at all for the rest of the drive.

Notice this the next time you guys go out on an 'extended' trip. The lights will dim while releasing the throttle and getting back on it {between shifting or in a gear}. Then after a few minutes it will go away and won't happen again.

Does this have something to do with operating temperature?

7LitreC5

My 02 does it too.

Red C6 Z06

I've never seen this on my '04, but then I don't do a whole lot of driving at night. Is it at all possible that the AC cycling could be a factor?

gst20psi

My 98 does it too. You can count between the "pulses" it’s the same amount of time between the lights dimming each time.

BayouVette

my 97 does it when using the windows and not that I put in a sub an amp when I crank it it goes to the beat. It gets aggrevating at night.