Brake light wiring question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**CPNE** · 04-12-2004, 10:18 AM

I know the following:

Brown = taillights
Lt green = backup lamps
Dk green and yellow = turn signals

But what about brake lights? When the brakes are applied does the power travel both the turn signal wires (dk green and yellow)or just one of them? I have both turn signals but only the RH brake light. My bulbs are 1157's and have tested to be good.

Thanks

JimKshortstep4x4 · 04-12-2004, 10:38 AM

Jeff,

Power goes through both wires for the brake lights with the turn signal switch in the middle.

If both of your turnsignals work, it is pretty certain that the problem is in your turn signal switch. Sometimes just replacing the upper part of the turn signal switch will fix the problem. It is easier to do that than it is to replace the whole switch.

Good luck!

Jim

Olden Days · 04-12-2004, 10:43 AM

assuming the 56 i once owned is the same, the brake switch just bypasses the flasher and sends power through the signal switch and on to the brake lamps on the same grn and yel wires. That is odd one would work and one would not. But I would start with the signal switch. (spay electric cleaner etc.) test for current where it comes back out of the colum.

**CPNE** · 04-12-2004, 10:48 AM

Thanks Jim/Oldendays. That is most likely where the problem is as I need to replace the turn signal switch in the column anyway. The plastic switch the signal lever attaches to is broken and works sporadically.

JimKshortstep4x4 · 04-12-2004, 10:59 AM

Jeff,

The broken part is what I was suggesting that you replace. They are held in place with plastic latches and are quite easy to replace with the wheel removed. Tilt and non-tilt "cancel plates" are the same, (not sure of the part name).

Jim

**CPNE** · 04-12-2004, 11:05 AM

Quote:

Originally posted by JimKshortstep4x4
Jeff,

The broken part is what I was suggesting that you replace. They are held in place with plastic latches and are quite easy to replace with the wheel removed. Tilt and non-tilt "cancel plates" are the same, (not sure of the part name).

Jim

Ya, I've been into a few columns before, but I was unaware of how the wiring for brake/turn signals actually worked. I think I'm set on this one.

04-12-2004, 10:18 AM	#1
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,662	Brake light wiring question I know the following: Brown = taillights Lt green = backup lamps Dk green and yellow = turn signals But what about brake lights? When the brakes are applied does the power travel both the turn signal wires (dk green and yellow)or just one of them? I have both turn signals but only the RH brake light. My bulbs are 1157's and have tested to be good. Thanks __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

04-12-2004, 10:48 AM	#4
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,662	Thanks Jim/Oldendays. That is most likely where the problem is as I need to replace the turn signal switch in the column anyway. The plastic switch the signal lever attaches to is broken and works sporadically. __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

04-12-2004, 10:38 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Jeff, Power goes through both wires for the brake lights with the turn signal switch in the middle. If both of your turnsignals work, it is pretty certain that the problem is in your turn signal switch. Sometimes just replacing the upper part of the turn signal switch will fix the problem. It is easier to do that than it is to replace the whole switch. Good luck! Jim

04-12-2004, 10:43 AM	#3
Olden Days Living In The Past Join Date: Nov 2003 Location: Rockies Posts: 709	assuming the 56 i once owned is the same, the brake switch just bypasses the flasher and sends power through the signal switch and on to the brake lamps on the same grn and yel wires. That is odd one would work and one would not. But I would start with the signal switch. (spay electric cleaner etc.) test for current where it comes back out of the colum.

04-12-2004, 10:59 AM	#5
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Jeff, The broken part is what I was suggesting that you replace. They are held in place with plastic latches and are quite easy to replace with the wheel removed. Tilt and non-tilt "cancel plates" are the same, (not sure of the part name). Jim



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