Adding 3rd brake light - The 1947 - Present Chevrolet & GMC Truck Message Board Network

nrb's70gmc · 02-25-2014, 12:46 AM

I was wondering how hard It would be to add a 3rd brake light to a non 3rd brake light truck cab. As far as wiring.

70LonghornCST · 02-25-2014, 12:49 AM

Not really, you'd need a template for the cargo housing, a cargo light, and would need to route a wire through your cab like the dome light, go out the firewall through one of the existing grommets, and tap into your brake light wire on your harness.

**PowerdbyChevy79** · 02-25-2014, 10:52 AM

Ya what he said...

nrb's70gmc · 02-26-2014, 01:22 AM

Is that how the factory setup is? Maybe lmc sells a pre made wiring set up. Even though it would not be hard to make your self.

70LonghornCST · 02-26-2014, 01:39 AM

The factory setup was only a cargo light, not a brake light. The wire from the cargo light would run parallel to the dome light wire and plug into the fuse box.

cdngearhead · 02-26-2014, 02:05 AM

Cool idea
Red led light with the factory clear lens

chuckmc8 · 02-26-2014, 05:33 AM

here ya go

http://67-72chevytrucks.com/vboard/s...d.php?t=200080

nrb's70gmc · 02-26-2014, 05:58 PM

well I had sort of a different idea other than stock
http://www.gorecon.com/product.php?p...-LENS&p_cat=48

Thundarr · 02-26-2014, 06:33 PM

I'm doing mine as we speak, but its the stock conversion style with LEDs.

Running the wire is really easy. Pull the exterior cargo light and the interior dome light. You will see that both lights have loose wiring that travels in the cavity over to the drivers side area where the fuel filler enters the cab. You can just feed the one positive wire right next to them with no fish rod or anything. Its wide open and easy to do. Chase that single wire under the carpet up to the fuse panel and tap into the rear brake lamp fuse location. Make sure to tap in at the out-going side of the fuse panel so you don't bypass the safety of the fuse and end up frying your $300+ fancy brake lamp. The ground can be joined right there into the same line as the Cargo and Dome lamp.

02-25-2014, 12:46 AM	#1
nrb's70gmc Registered User Join Date: Sep 2008 Location: magalia,ca Posts: 366	Adding 3rd brake light I was wondering how hard It would be to add a 3rd brake light to a non 3rd brake light truck cab. As far as wiring. __________________ 1970 2wd 3/4 ton- 2004 crate 350 thorley tri-y headers-edelbrock performer eps manifold 600cfm performer carb, crane cams energizer cam,lifters, dual 2.5 magnaflows, mallory HEI, powermaster 140 amp altenator, griffen aluminum radiator.(8 MPG)

02-25-2014, 12:49 AM	#2
70LonghornCST Moderator Join Date: Jun 2008 Location: Modesto, CA Posts: 5,775	Re: Adding 3rd brake light Not really, you'd need a template for the cargo housing, a cargo light, and would need to route a wire through your cab like the dome light, go out the firewall through one of the existing grommets, and tap into your brake light wire on your harness. __________________ 2018 Chevy Crew Cab 2006 Impala SS 1965 Plymouth Sport Fury 1970 Chevy Longhorn Bucket Seats Shoulder Belts Front Tow Hooks Factory Air Factory Speedwarning, Tach & Vaccum Factory Tilt CST Package AM/FM Radio Bumper Guards Richard 70 Longhorn CST Build Adding an AM/FM Decal

02-25-2014, 10:52 AM	#3
PowerdbyChevy79 Senior Member Join Date: Apr 2013 Location: Houston,Tx Posts: 754	Re: Adding 3rd brake light Ya what he said...

02-26-2014, 01:22 AM	#4
nrb's70gmc Registered User Join Date: Sep 2008 Location: magalia,ca Posts: 366	Re: Adding 3rd brake light Is that how the factory setup is? Maybe lmc sells a pre made wiring set up. Even though it would not be hard to make your self. __________________ 1970 2wd 3/4 ton- 2004 crate 350 thorley tri-y headers-edelbrock performer eps manifold 600cfm performer carb, crane cams energizer cam,lifters, dual 2.5 magnaflows, mallory HEI, powermaster 140 amp altenator, griffen aluminum radiator.(8 MPG)

02-26-2014, 01:39 AM	#5
70LonghornCST Moderator Join Date: Jun 2008 Location: Modesto, CA Posts: 5,775	Re: Adding 3rd brake light The factory setup was only a cargo light, not a brake light. The wire from the cargo light would run parallel to the dome light wire and plug into the fuse box. __________________ 2018 Chevy Crew Cab 2006 Impala SS 1965 Plymouth Sport Fury 1970 Chevy Longhorn Bucket Seats Shoulder Belts Front Tow Hooks Factory Air Factory Speedwarning, Tach & Vaccum Factory Tilt CST Package AM/FM Radio Bumper Guards Richard 70 Longhorn CST Build Adding an AM/FM Decal

02-26-2014, 02:05 AM	#6
cdngearhead Registered User Join Date: Feb 2014 Location: Kelowna BC Posts: 73	Re: Adding 3rd brake light Cool idea Red led light with the factory clear lens

02-26-2014, 05:33 AM	#7
chuckmc8 It's alsways something..... Join Date: Nov 2008 Location: Douglasville GA Posts: 1,171	Re: Adding 3rd brake light here ya go http://67-72chevytrucks.com/vboard/s...d.php?t=200080 __________________ 1968 RS Camaro 'Vert Matching number 327 and M21 Muncie 1968 C10 Black with red interior and orig paint. 5.3 / 4l60e,3:73 POSI 17" Torq Thrusts 1968 CST 514 Red with black interior. Buddy Buckets, Factory A/C, PS, PB- 20" AR custom shop TT, 5.3 and 4l60e

02-26-2014, 05:58 PM	#8
nrb's70gmc Registered User Join Date: Sep 2008 Location: magalia,ca Posts: 366	Re: Adding 3rd brake light well I had sort of a different idea other than stock http://www.gorecon.com/product.php?p...-LENS&p_cat=48 __________________ 1970 2wd 3/4 ton- 2004 crate 350 thorley tri-y headers-edelbrock performer eps manifold 600cfm performer carb, crane cams energizer cam,lifters, dual 2.5 magnaflows, mallory HEI, powermaster 140 amp altenator, griffen aluminum radiator.(8 MPG)

02-26-2014, 06:33 PM	#9
Thundarr Registered User Join Date: May 2013 Location: Coppell, Texas Posts: 176	Re: Adding 3rd brake light I'm doing mine as we speak, but its the stock conversion style with LEDs. Running the wire is really easy. Pull the exterior cargo light and the interior dome light. You will see that both lights have loose wiring that travels in the cavity over to the drivers side area where the fuel filler enters the cab. You can just feed the one positive wire right next to them with no fish rod or anything. Its wide open and easy to do. Chase that single wire under the carpet up to the fuse panel and tap into the rear brake lamp fuse location. Make sure to tap in at the out-going side of the fuse panel so you don't bypass the safety of the fuse and end up frying your $300+ fancy brake lamp. The ground can be joined right there into the same line as the Cargo and Dome lamp. __________________ 1971 GMC C15 Sierra Grande SWB 1972 Chevy C10 Custom Deluxe LWB 2018 GMC Yukon Denali



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