MY BRAKE LIGHTS DO NOT WORK WITH KEY ON

  • Tiny
  • zdaily
  • 1994 Chevrolet Silverado

But do with the key off. My brake switch works and has power but not the multifunction switch. I have traced it through the dash but it dissappears behind the gauges. I dont know where the brake switch and the multi switch intersect

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Wednesday, October 10th, 2012 AT 2:28 AM

14 Replies

  • Tiny
  • ASEMaster6371
  • Expert
  • 25,556 posts

Do the brake lights work with the key off?

Roy

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Wednesday, October 10th, 2012 AT 2:36 AM
  • Tiny
  • zdaily
  • Member

Yes they do, but ive been messing with so much that just now they do not

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Wednesday, October 10th, 2012 AT 2:42 AM
  • Tiny
  • KHLow2008
  • Expert
  • 41,997 posts

Except for the high mount brake light, the other stop lights are linked to the hazard/turn signal switch and that shuld be the component you should be looking at for the fault.

Refer to the schematics.

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Wednesday, October 10th, 2012 AT 2:43 AM
  • Tiny
  • zdaily
  • Member

There is no power going to the signal switch. This is where I am getting stumped

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Wednesday, October 10th, 2012 AT 2:48 AM
  • Tiny
  • zdaily
  • Member

I have a new switch and that did not change anything. There is no power to the switch in general

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Wednesday, October 10th, 2012 AT 2:56 AM
  • Tiny
  • zdaily
  • Member

The yellow wire from the brake switch has power. But the white wire that connects to the signal switch has power for a seconds and then dims to nothing. This is with the key on. Why would this happen?

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Wednesday, October 10th, 2012 AT 3:09 AM
  • Tiny
  • KHLow2008
  • Expert
  • 41,997 posts

When power to White wire fades, check Yellow wire again. If power is available, the brake switch is the one causing the problem.

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Wednesday, October 10th, 2012 AT 3:39 AM
  • Tiny
  • zdaily
  • Member

So I just installed a new brake switch and that did not fix my problem. And the grounds in the back near the lights are all good. I am losing power in between the signal switch, and the brake switch. Is the wire grounded somewhere in between that might have rattled lose?

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Thursday, October 11th, 2012 AT 1:12 AM
  • Tiny
  • zdaily
  • Member

The yellow wire from the brake switch, is spliced to 4 other yellow wires, from there two wires run up and behind the dash. Another runs to the relays that still has power and the other runs to a junction that is connected to 5 other wires that also stays hot. The 2 wires that run up and behind my dash, I don't know where they lead but a white wire comes from there back down and to the signal switch. What happens in between?

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Thursday, October 11th, 2012 AT 1:19 AM
  • Tiny
  • KHLow2008
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  • 41,997 posts

You did not specify the exact model of your vehicle resulting in me posting the wrong schematics previously. Here are the correct schematics.

The two wires going up to dash should be for the the cruise control and auxiliary usage.

Inbetween is the center high mount stoplight relay, which is located at right hand side of cowl, in engine compartment. The White wire to signal switch must have battery voltage when brake switch is operated. If no voltage is present you need to check the relay.

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Thursday, October 11th, 2012 AT 2:55 AM

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