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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: 1978 K20 on May 16, 2011, 01:45:14 am

Title: I'm stumped!!
Post by: 1978 K20 on May 16, 2011, 01:45:14 am

So here is the deal.

I've got a 78 K20, The right brake light is having problems. First thing I did is changed the bulb (twice) and still nothing. The weird part is that there is power to the socket. It is a 1157, so it is dual filament. When only the tail light is only on there is power to one side, and when I press the brake pedal there is power to both sides (like there should be.) BUT THE LIGHT STILL ISNT WORKING!

It wasn't working last night, yet it worked when I left work, and didnt work when I backed into my driveway (2ish miles away.)

ANY ideas are welcome. Thanks!

-John

Title: Re: I'm stumped!!
Post by: Irish_Alley on May 16, 2011, 10:02:57 am

bad ground

Title: Re: I'm stumped!!
Post by: 1978 K20 on May 16, 2011, 10:36:30 am

But where is a ground in that circut?

Title: Re: I'm stumped!!
Post by: VileZambonie on May 16, 2011, 05:02:19 pm

(http://www.73-87chevytrucks.com/techinfo/wiring_diagrams/77-80_chass_rr_light.jpg)

Title: Re: I'm stumped!!
Post by: VileZambonie on May 16, 2011, 05:02:38 pm

http://www.73-87chevytrucks.com/techinfo/wiring_diagrams/77-80_chass_rr_light.jpg

Title: Re: I'm stumped!!
Post by: Irish_Alley on May 16, 2011, 09:28:13 pm

could also be a bad socket

Title: Re: I'm stumped!!
Post by: 1978 K20 on May 17, 2011, 12:18:46 pm

Unless I have gotten two bad sockets in a row, I am ruling out a bad socket. I think my best bet is going to be to shoot wiring and try to find a bad ground.

Title: Re: I'm stumped!!
Post by: Irish_Alley on May 17, 2011, 06:38:46 pm

did you change the bulbs and sockets or just the bulbs

Title: Re: I'm stumped!!
Post by: VileZambonie on May 17, 2011, 06:57:25 pm

If you think its a bad ground runa jumper wire from the the housing to a good ground and see if it works.

Title: Re: I'm stumped!!
Post by: fitz on May 17, 2011, 08:19:58 pm

Quote from: VileZambonie on May 17, 2011, 06:57:25 pm

If you think its a bad ground runa jumper wire from the the housing to a good ground and see if it works.

You can count on Vile for a solid answer. I would have said to run the jumpers into the left brake light and call it a day.