Headlights Dim when Braking?
Thread Starter
Instructor
Joined: Aug 2006
Posts: 134
Likes: 0
From: Apple Valley MN
Headlights Dim when Braking?
Ok - I'm new to C5's - and may be just looking for problems. Last night, I noticed when I stepped on the Brakes, the Headlights dimmed slighlty. At first I thought i was nuts - but my wife also notcied it. I then noticed the Battery Gauge dropped a little also. Is this a weak battery? Or something larger?
Thread Starter
Instructor
Joined: Aug 2006
Posts: 134
Likes: 0
From: Apple Valley MN
I bought the car this past weekend with only 4,451 miles on it. The previous owner basically did not drive it. I does not have the orginal battery in it - it has a Sears Diehard Platium - but it looks small in size. I suspect it never had a battery tender on it. I will get the battery checked. Should get an orginal GM battery seeing as the car still has all the paper tabs under hood and on the supension parts?
Racer
Joined: Sep 2006
Posts: 464
Likes: 2
From: New Bern NC
Racer
Joined: Sep 2006
Posts: 280
Likes: 0
Ok - I'm new to C5's - and may be just looking for problems. Last night, I noticed when I stepped on the Brakes, the Headlights dimmed slighlty. At first I thought i was nuts - but my wife also notcied it. I then noticed the Battery Gauge dropped a little also. Is this a weak battery? Or something larger?
Mine was the alternator.
Good luck !!
Drifting
Joined: Feb 2005
Posts: 1,643
Likes: 167
It can be either one, but I'd start with the battery because it's easier to check and replace than the alternator. If it turns out the battery is good, then I'd check the alternator next.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Former Vendor
Joined: Nov 2005
Posts: 8,995
Likes: 2
From: Spring Texas
St. Jude Donor '08
Do the "big 3" mod. This will hold you over until you figure out the problem.
Big 3: is 3 lengths of 4 awg wire from
Alternator (+) to battery (+)
Alternator mounting bolt to Frame
Battery (-) to Frame
this significantly reduces voltage drop across your electrical system. (the primary cause of headlight dimming)
Big 3: is 3 lengths of 4 awg wire from
Alternator (+) to battery (+)
Alternator mounting bolt to Frame
Battery (-) to Frame
this significantly reduces voltage drop across your electrical system. (the primary cause of headlight dimming)
Thread Starter
Instructor
Joined: Aug 2006
Posts: 134
Likes: 0
From: Apple Valley MN
Thanks everyone - I will check it out this evening again at idle then will start with making sure the connections are clean and solid. Ten move on to the Battery check and Alt if necessary. I post what i find so it can maybe help someone else. 
Safety Car
Joined: Dec 2002
Posts: 4,869
Likes: 2
From: San Diego CA
Same problem here that I just noticed in the past week. I would have been surprised if I hadn't noticed it in the previous 25,000 miles that I've driven my 03. I walked out to drive it home this morning and had the following sequence of events:
1. the remote wouldn't work - had to use the key.
2. the lights didn't come on when I open the door - assume the battery is dead and I'm ticked b/c I've been up working all night and the battery was an Optima red top that's only a year or so old.
3. try to start the car and it actually starts - happy that I'll get home, but still mystified by #1 and #2.
4. car dies as I back up and column locks - now I'm pissed again.
5. Restart car and I'm able to get home.
Haven't had a chance to check it again today, but I'm assuming that I'm going to have a little fun chasing this gremlin down. Any ideas beyond battery, connections, etc.? As additional info, had to have the ABS pump and all the AH electronic module replaced a few weeks ago - fortunately under GMPP as it would have been a $3300 bill. I wondered if that played any role in the headlight dimming with the brakes only b/c of the proximity in the fix and the new problem.
1. the remote wouldn't work - had to use the key.
2. the lights didn't come on when I open the door - assume the battery is dead and I'm ticked b/c I've been up working all night and the battery was an Optima red top that's only a year or so old.
3. try to start the car and it actually starts - happy that I'll get home, but still mystified by #1 and #2.
4. car dies as I back up and column locks - now I'm pissed again.
5. Restart car and I'm able to get home.
Haven't had a chance to check it again today, but I'm assuming that I'm going to have a little fun chasing this gremlin down. Any ideas beyond battery, connections, etc.? As additional info, had to have the ABS pump and all the AH electronic module replaced a few weeks ago - fortunately under GMPP as it would have been a $3300 bill. I wondered if that played any role in the headlight dimming with the brakes only b/c of the proximity in the fix and the new problem.
