Light dimming question
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Joined: Sep 2004
Posts: 77
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From: San Antonio Texas
Light dimming question
I have a 97 and recently I have been noticing (especially when sitting at a light) that the lights dim for a split second every 3.5 seconds or so. Not just the headlights but the speedo and everything. Any thoughts on what is causing this?
Le Mans Master
Joined: Feb 2002
Posts: 6,937
Likes: 21
From: Waldorf MD
Make sure your battery terminals are clean and tight (11 ft-lbs), worked for me.
Make sure you don't over torque the terminals, this is the major cause of side terminal batteries leaking acid. Since your computer is under the battery you don't want it leaking.
Make sure you don't over torque the terminals, this is the major cause of side terminal batteries leaking acid. Since your computer is under the battery you don't want it leaking.
Racer
Joined: Jan 2006
Posts: 265
Likes: 1
From: OKC OK
my 97 has been doing the same thing for months and i have check all i could find..if you figure it out please pm me w/the answer....i am baffled...new battery....i have noticed the dic reading erratic numbers around 12-13.5 i dont know if the altenator regulator or bad grounds??? i have cleaned several..but dont know where all of them are located.........ps..anyone know what the ground wire goes to that is located on the passenger side frame..outside battery box?...mine is rusted and its the only one i havent cleaned yet.....
Melting Slicks
Joined: Jul 2006
Posts: 2,094
Likes: 5
From: The 7th layer of hell - Western Washington
A possibility as to what is happening in your case, just a shot in the dark here. Is this only happening when you have the A/C or defrost on (or the automatic climate control has either on)? With the constant cycling of the A/C ompressor it may be adding just enough extra load on the system to slightly dim the lights.
Thread Starter
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Joined: Sep 2004
Posts: 77
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From: San Antonio Texas
I had a chance last night to sit and listen and watch the lights for a minute and the first thing I noticed is that looking at the analog volt gauge, it is at 13.0 volts and drops very very slightly when when the lights dim. The really interesting thing is that each time it dipped I heard a slight whining noise. As a listened more carefully I figured out it was my fuel pump starting to spool up and then quickly being shut off. I have no idea why it would keep trying to balance the tanks and shut off before it could do anything but that is what it sounded like.
Melting Slicks
Joined: Dec 2004
Posts: 2,394
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From: Bay Area CA
13.0 is low IMO and from my experience with my 01z. I replaced the original battery very soon after I bought it in november of last year. With that battery I ran 13.5 to 13.6 pretty consistently. With my Optima red top I run 13.9 to 14.2 during the daytime (no a/c) and a solid 13.8 with the headlights on. I can make it dip to the low 12's though with the stereo cranked up 
I think either you are getting a more than normal load from some electronic component (like the fuel pump thing you mentioned) or your alternator is not charging as it should be.
Fej
I think either you are getting a more than normal load from some electronic component (like the fuel pump thing you mentioned) or your alternator is not charging as it should be.
Fej
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Burning Brakes
Joined: Mar 2006
Posts: 1,195
Likes: 25
From: Tacoma WA
Yeah i noticed a similar problem on my '97... sometimes when various components turn on the lights will dim for a split second...
Like cruising along and then applying brakes causes lights to dimm for a fraction of a second, AC kicking in, and/or various other electronic components all seem to *sometimes* cause the lights to dim for a split second...
I'll check my terminals (Bran New Optima Red Top) and i'll check my voltage ranges while running...
Dan
Like cruising along and then applying brakes causes lights to dimm for a fraction of a second, AC kicking in, and/or various other electronic components all seem to *sometimes* cause the lights to dim for a split second...
I'll check my terminals (Bran New Optima Red Top) and i'll check my voltage ranges while running...
Dan
Burning Brakes
Joined: Mar 2006
Posts: 1,195
Likes: 25
From: Tacoma WA
So OMW home from work i did some Volt Watching...
I noticed - with all the electronics off at idle not warmed up i'm sitting at about 13.7 Volts
When i turned the vents on high, the AC on, the Defogger, and Rear Defroster, Stereo (Resonabley) Sirius Satellite Radio, Headlights, sat at idle, it dropped to 13.3
From there, if i pressed the brake it would drop a little, or flipped on the turn signal it would drop a little (like to 13.0-13.1 then back up instantly) But while driving, if i approached a turn and hit the brake, clutch (downshift) and turnsignal all at once, with all those other things still running it would drop to 12.0... But thats only like a quarter of a second, then it springs right back up to 13.3-13.5
So i was never under 13.3 for more than a fraction of a second, but for that fraction my lights do dim some... is that normal? I plan on inspecting the grounds if i get off work before dark soon...
Dan
I noticed - with all the electronics off at idle not warmed up i'm sitting at about 13.7 Volts
When i turned the vents on high, the AC on, the Defogger, and Rear Defroster, Stereo (Resonabley) Sirius Satellite Radio, Headlights, sat at idle, it dropped to 13.3
From there, if i pressed the brake it would drop a little, or flipped on the turn signal it would drop a little (like to 13.0-13.1 then back up instantly) But while driving, if i approached a turn and hit the brake, clutch (downshift) and turnsignal all at once, with all those other things still running it would drop to 12.0... But thats only like a quarter of a second, then it springs right back up to 13.3-13.5
So i was never under 13.3 for more than a fraction of a second, but for that fraction my lights do dim some... is that normal? I plan on inspecting the grounds if i get off work before dark soon...
Dan
Burning Brakes
Joined: Sep 2003
Posts: 886
Likes: 87
From: Largo FL
Originally Posted by Oldvetter
Make sure your battery terminals are clean and tight (11 ft-lbs), worked for me.
Make sure you don't over torque the terminals, this is the major cause of side terminal batteries leaking acid. Since your computer is under the battery you don't want it leaking.
Make sure you don't over torque the terminals, this is the major cause of side terminal batteries leaking acid. Since your computer is under the battery you don't want it leaking.
Same with me - when I first got my 98 the lights would dim every few seconds, the voltage had a wide fluctuation and the lights would not always pop up first time. Cleaned and tighten the battery connections, solved all three problems -
Safety Car
Joined: Feb 2004
Posts: 4,208
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From: Rochester MN
CI 5-6-7-8 Veteran
St. Jude Donor '04-'05-'06-'07
NCM Ambassador
I'm almost wondering if installing a capacitor (like the ones used for sound systems) might smooth out the power fluxuations..
