1988 GMC C1500 Brake lights

DSISTRUNK

MEMBER
1988 GMC C1500
V8
2WD
AUTOMATIC
109,000 MILES

I have replaced the brake light switch on my daughters 88 GMC pickup and still have the same problem. The brake lights do nothing when you step on the brake pedal, however when you turn on the parking or the headlights the brake lights light up perfectly along with the tail lights. All hazards/signals work fine and the bulbs and fuses are all good. Could this be the headlights switch? Or do you have any other ideas?

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,867 POSTS

Hi:
With the lights off, are you getting power to the switch?

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Monday, December 15th, 2008 AT 5:00 PM

DSISTRUNK

MEMBER
2 POSTS

Hi, yes it is getting power to the switch with the lights off. I have since replaced the headlight switch and still have the same problem.

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Monday, December 15th, 2008 AT 5:21 PM

JACOBANDNICKOLAS

MECHANIC
109,867 POSTS

Hi:
I need you to check the tail light sockets of damage. If they are ok, check the socket for power when the brake is applied. Make sure the test light has a good ground. At this point, something is telling me that there is a ground problem. When you have the lights on, the brake lights are grounding through the switch. Also, at the brake switch, have you checked for power out with the lights off?

Joe

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Monday, December 15th, 2008 AT 5:47 PM