Help! Headlights dim when brake applied

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Feb 4, 2005 | 01:45 AM

Y2k Vette Pilot

Thread Starter

Racer

Joined: Oct 2002

Posts: 299

Likes: 1

From: Coastal Sektor, Southern Province, Peoples Republik of Kalifornia

Help! Headlights dim when brake applied

Question....when applying brakes my headlights dim....is this a voltage regulator problem? If so, do I need a new voltage regulator or??? Any help is GREATLY appreciated...PS The dimming is not severe, but noticeable...

Feb 4, 2005 | 07:07 PM

Fleet1

Racer

Joined: Nov 2004

Posts: 377

Likes: 0

From: Houston Texas

Quote:

Originally Posted by Y2k Vette Pilot

Have your battery checked. Thats what mine did before in died.

Feb 4, 2005 | 07:11 PM

mdbennes

Safety Car

Joined: Feb 2001

Posts: 4,494

Likes: 8

From: Niceville, FL

Mine is doing the same thing, but not all the times....Voltage is showing good though

Feb 4, 2005 | 11:48 PM

hbrown

3rd Gear

Joined: Oct 2004

Posts: 3

Likes: 0

Check your battery connections to ensure they are tight. These new electronic cars require tight connections.

Feb 5, 2005 | 07:13 AM

Bill Curlee

Tech Contributor

Joined: Dec 1999

Posts: 32,910

Likes: 2,402

From: Anthony TX

CI 6,7,8,9,11 Vet

St. Jude Donor '08

Your battery is a storrage device that holds reserve voltage and current and releases it when it is needed. Your alternator provides current and voltage to charge the battery and run the loads within your vehicle. Normaly your alternator puts out more voltage than the battery is rated at , say 13+ volts. This is required to charge the battery. When you apply a load on your electrical system, you load down the alternator. The variation that you see in your headlights seems to be normal. Many forum member (myself included) have expierenced this issue. As long as your not droping below 12.5 volts, your alternator is still outputing.
As stated previously, if your voltage fluctuation is excessive, you could have a bad/dirty battery terminal connection, bad ground or a devective regulator. The regulator is inside the alternator. A good automotive electrical shop will be able to test it and determine if it is good or bad.

BC

Feb 5, 2005 | 11:10 AM

Got uid0

Le Mans Master

Joined: Mar 2002

Posts: 8,466

Likes: 51

St. Jude Donor '17

running aftermarket stereo amps? Pulling to many amps than what your alt is supplying.

Step up to a larger battery with more cold cranking amps to help with dimming issues and get a better alternator for the amps if needed

Feb 5, 2005 | 12:03 PM

Mighty-Mouse

Burning Brakes

Joined: Dec 2004

Posts: 1,234

Likes: 2

From: New Jersey

This may not be related but GM has a bulletin out on some 2000 ABS equipped vehicles (not the Corvette) on dimming headlights.

Quote:

Condition: Headlights dim and/or flicker while driving

Repair Procedure: If the EBCM loses a wheel-speed-sensor signal, it will activate the ABS motor momentarily. Since the motor may draw up to 100 amps, the lights will dim or flicker during the cycle. The brakes do not have to be applied for this condition to exist. The loss of a signal could be caused by faulty wiring, a bad wheel-speed sensor or sensor ring, or air gap (worn brakes).

Also look at the stop light switch mounted on the brake pedal, I believe it's attached at the top of the arm near the bracket. Make sure the connector isn't lose. Also you can disconnect the connector, then see if the headlights dim when you apply the brake. Obviously don't drive around with the switch disconnected