electrical hep; brake lights - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Frankd · 01-23-2005, 12:40 PM

I have a 84 GMC 3+3 1 ton. had a turn signal problem , the rear wiring was a buggered up, so I replaced the rear wiring with a harness from a 78 1/2 ton. now everthing works but the turn signals and the brake lights. when I hit the brakes both turnsinal indicators on the dash come on , but no brake lights. and no turn signals. before I did this the left turn signal worked and left brake light. any clues ?

rolson1039 · 01-23-2005, 02:42 PM

are ya sure you have the right bulbs in the sockets i know one time i put an 1156 bulb in a socket which required an 1157 and it did all kinds of crazy things.. may wanna check all the sockets in the truck

magnethead · 01-23-2005, 04:23 PM

I'm not sure that all years match electrically..esp. if you went from half to 1 ton, 1 tons are different electrically due to the extra roof and fender lights. Can't tell ya for sure, but start doing some wire tracing. Haines manual?

weekender · 01-23-2005, 10:56 PM

I just done mine, you should have a yellow, brown, green, not sure the colar of the backup lite. And of course the ground, brake lite goes through the turn sig. wire, brn. wire will be marker lites and lic. plate lite, and then the backup lite. Make sure that you have the right lite plug in the right hole, check the bulbs, rolsin has a good point, check grounds, good luck.

01-23-2005, 12:40 PM	#1
Frankd Registered User Join Date: Nov 2003 Location: Mauk, Ga Posts: 76	electrical hep; brake lights I have a 84 GMC 3+3 1 ton. had a turn signal problem , the rear wiring was a buggered up, so I replaced the rear wiring with a harness from a 78 1/2 ton. now everthing works but the turn signals and the brake lights. when I hit the brakes both turnsinal indicators on the dash come on , but no brake lights. and no turn signals. before I did this the left turn signal worked and left brake light. any clues ? __________________ 72 c-10 81 c-30 67 c-10 just sittin in the woods) 70 C-10 " " " " to compleete frames 67, 70 - in woods 2002 toyota tundra. 12 yr old son has , 72 Charger, 78 Ramcharger and 85 ford wrecker

01-23-2005, 02:42 PM	#2
rolson1039 Registered User Join Date: Oct 2002 Location: NJ Posts: 404	are ya sure you have the right bulbs in the sockets i know one time i put an 1156 bulb in a socket which required an 1157 and it did all kinds of crazy things.. may wanna check all the sockets in the truck __________________ so many trucks so little time!!!

01-23-2005, 04:23 PM	#3
magnethead 7000 #'s of american IRON Join Date: Dec 2004 Location: north tx Posts: 883	I'm not sure that all years match electrically..esp. if you went from half to 1 ton, 1 tons are different electrically due to the extra roof and fender lights. Can't tell ya for sure, but start doing some wire tracing. Haines manual?

01-23-2005, 10:56 PM	#4
weekender Registered User Join Date: Oct 2003 Location: Jewett Illinois Posts: 32	I just done mine, you should have a yellow, brown, green, not sure the colar of the backup lite. And of course the ground, brake lite goes through the turn sig. wire, brn. wire will be marker lites and lic. plate lite, and then the backup lite. Make sure that you have the right lite plug in the right hole, check the bulbs, rolsin has a good point, check grounds, good luck.



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