Lights dim when hitting the brake.
Sergeant
Joined: Jul 2001
Posts: 443
Likes: 1
From: Clarksville FL
Re: Lights dim when hitting the brake. (GlockLT4)
My speedo display does this, I haven't noticed the lights doing it though. Mine does it with the old battery or a new optima also. I think someone mentioned it being a loose ground or alternator prob, sorry can't help further. :cheers:
Le Mans Master
Joined: Jun 2001
Posts: 6,694
Likes: 3
From: Less Talk, More WOT | Houston TX
Re: Lights dim when hitting the brake. (GlockLT4)
mine started to do that right before the battery crapped out.......couldnt hurt to take it down to autozone and have it checked to be safe.....
Drifting
Joined: Oct 2001
Posts: 1,759
Likes: 0
From: Round Rock,Austin, Texas
Re: Lights dim when hitting the brake. (GlockLT4)
I have had that problem for a while now. I dont know what its is either. I figure when I do my cam swap I will look at the wire connections on opti. I am putting new wires on anyways so... :rolleyes:
Thread Starter
Team Owner
Joined: Apr 2001
Posts: 22,267
Likes: 3
From: Dallas TX
Re: Lights dim when hitting the brake. (RadPolo96)
I have had that problem for a while now. I dont know what its is either. I figure when I do my cam swap I will look at the wire connections on opti. I am putting new wires on anyways so... :rolleyes:
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Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Lights dim when hitting the brake. (GlockLT4)
All of the brake lights draw a decent amount of current (6-8 amps, my guess).
The voltage regulator in the alternator attempts to maintain 14.7 volts across the battery at all times, but its response time isn't instantaneous, so when you push on the brake the battery voltage will momentarily drop until the alternator responds and returns the voltage to 14.7 volts. So what you see is a momentary flicker of all of your lights, dash, headlights, etc., when you press on the brake. This is normal. With the engine at idle, the alternator cannot deliver its rated output current due to low rpm and it may not be able
to recover the battery voltage to 14.7 volts. If your dash voltmeter shows a drop that stays dropped with the brakes on and road rpm (1500 or above), then I would suspect that you have an alternator that is at the end of its life and will soon leave you stranded somewhere.
The voltage regulator in the alternator attempts to maintain 14.7 volts across the battery at all times, but its response time isn't instantaneous, so when you push on the brake the battery voltage will momentarily drop until the alternator responds and returns the voltage to 14.7 volts. So what you see is a momentary flicker of all of your lights, dash, headlights, etc., when you press on the brake. This is normal. With the engine at idle, the alternator cannot deliver its rated output current due to low rpm and it may not be able
to recover the battery voltage to 14.7 volts. If your dash voltmeter shows a drop that stays dropped with the brakes on and road rpm (1500 or above), then I would suspect that you have an alternator that is at the end of its life and will soon leave you stranded somewhere.
Thread Starter
Team Owner
Joined: Apr 2001
Posts: 22,267
Likes: 3
From: Dallas TX
Re: Lights dim when hitting the brake. (jfb)
It's just a momentary drop like you said, but that didn't happen with my '94, so that's why i was curious. I'm pretty sure it's not the alternator as the voltages stay return to normal very quickly.
Racer
Joined: Nov 2002
Posts: 261
Likes: 0
From: Ft Walton Beach FL
Re: Lights dim when hitting the brake. (jfb)
I think its normal. It only does it for a brief second right? Mine does that too. My speedo dims in the same manner when I'm listening to a song that has alot of deep bass and the stereo is turned up pretty loud. I dont think there's anything wrong with your car. JMO Good Luck :thumbs:
Thread Starter
Team Owner
Joined: Apr 2001
Posts: 22,267
Likes: 3
From: Dallas TX
Re: Lights dim when hitting the brake. (spdrcrj)
yeah, same thing with bass. I nmy blazer i had to put a 1farad cap in my car to keep the headlights from dimming too much, lol. I guess 2000 watts is too much :D
Advanced
Joined: Jan 2003
Posts: 94
Likes: 0
From: Potomac MD
Re: Lights dim when hitting the brake. (GlockLT4)
My '95 has started this too. Noticed that the battery is having issues holding a charge, so its time to swap it out for a new one (every 18 to 24 months). I'll see what happens with a fresh battery.
