Find a wiring brake light wiring diagram?

Tiny
APRILCHRISTMAS83
  • MEMBER
  • 2005 CHEVROLET SILVERADO
  • 0.8L
  • V8
  • 4WD
  • AUTOMATIC
  • 23,300 MILES
I can't seem to find a wiring brake light wiring diagram for my friends 2005 Chevrolet Silverado 2500 HD
Sub-Model:
Base
Engine:
8 Cylinders 6.0L Vortec Compressed Natural Gas (CNG) he had tried to fix the little light in the middle in the back you know the cargo light or whatever on the outside so I can roof of the truck and his brake lights stop working he changed the module and he needs a wiring diagram we're both on a fixed income and I'm confused and he's at his Wit's end trying to figure it out and trying to find one without being charged a million dollars so if you can get me a wiring diagram that would be great thank you for the brake lights

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Monday, February 2nd, 2026 AT 4:34 PM

5 Replies

Tiny
STEVE W.
  • MECHANIC
  • 15,546 POSTS
Wow, he has a CNG truck? Those are RARE around here, unless you work for one of the pipelines, or converted your own.
I'll attach the oem and the redrawn diagrams. There is a fuse for the center brake light that may have blown. If he lost all brake lights then check the fuse in the box under the hood, the other two are under the dash.
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Tuesday, February 3rd, 2026 AT 11:30 AM
Tiny
STUMPED & FRUSTRATED
  • MEMBER
  • 8 POSTS
High I sent a questionable my brake lights Steve W replied yes the answer was helpful I did
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Wednesday, February 4th, 2026 AT 9:19 AM
Tiny
STUMPED & FRUSTRATED
  • MEMBER
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I did everything you suggested all the fuses are good no visible burnt connections, I'm not getting power to the 15 amp fuse drivers side in the dash the brake light switch is good I ran a hot wire from the inside fuse block to the orange wire on the switch still no brake light
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Wednesday, February 4th, 2026 AT 9:25 AM
Tiny
STUMPED & FRUSTRATED
  • MEMBER
  • 8 POSTS
It's not a CNG She made a mistake, I did rum a hot wire to one side of the 15 amp fuse the top light came on then to the other side and the bottom lights came on any suggestions thank you
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Wednesday, February 4th, 2026 AT 9:29 AM
Tiny
STEVE W.
  • MECHANIC
  • 15,546 POSTS
No problem, I was hoping I found a unicorn ! The jumper to the interior fuses making the lights work at least tells you it isn't in the wiring. The 15 amp in the dash only gets power if the brake pedal switch is on as that switch passes power to the dash box and that sends power to those 2 fuses. The orange wire should be power from the fuse in the front box. Then the switch coming on sends power to the white wire. Take the power jumper you have and touch it to the white wire on the switch. If the lights turn on then that wire is good to the rear fuses, if they don't then that wire has an issue from the switch to the fuse box.
Grab a simple test light and verify that the 25 amp in the box has power to both sides, those boxes like to corrode underneath. If you get a light on both sides of the fuse but nothing on the orange wire on the switch, it could be a bad connection or wire.
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Wednesday, February 4th, 2026 AT 5:05 PM

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