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Ivan, ASE Certified Master Technician
Category: GM
Satisfied Customers: 4871
Experience:  ASE Master Tech.20+ years exp. 9 years self employed. Participant on AutoLab Radio broadcast
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1991 GMC: brake lights (stop) wont come on..gone bad..relay

Resolved Question:

1991 GMC Sierra brake lights (stop) wont come on. No power to the fuse box? What is anything is between the battery and the fuse box that may have gone bad, a relay or something? Could it just be a bad wire?
Submitted: 7 years ago.
Category: GM
Expert:  Ivan replied 7 years ago.

HelloCustomer you have a junction block on the firewall that is the original for this circuit and the location of fusible links. If that fuse is dead, you must have burnt a fusible link at this location. Look at this diagram and it will help you locate the position at the junction block.


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Customer: replied 7 years ago.
Rechecked that fuse with the key on and now I have power. But the brake lights still dont work. I was told, and now see, that there is another brake light swith higher up than the one i replace but I cant tell how to disconnect/remove it. What is holding it in place. It must be the swith to the cruise control.
Expert:  Ivan replied 7 years ago.

This is the switch that is for the stop lights. The one higher up is for Cruise control . My diagrams show a white wire that comes out of this stop light switch and feeds into the directional switch to go back to the stop lights. Go back and look and see if this makes sense on your truck. Here is a picture of the stop lamp switch.





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