proud_sierra_driver

Ok have a 1990 GMC sierra. It is not really stock at all but the lights are. The problem is when I turn on the blinker it works fine but if I turn on the head lights or running lights they blink really slow. Now when I hit the brake with any of the other lights on they stop blinking completely.

The only thing I can think of is when I bought the truck the light mount for the left rear blinker/brake/reverse light was not working when I bought the truck so I took the mount off of my 1995 GMC sierra that does not run and put it on the 90. But as far as I know they are compatible.

So does anyone know what could be causing this?

suzuki-guy

Sounds like you got a bad ground somewhere.

proud_sierra_driver

Lol I am good with mechanics but not with electronics. How would I go about finding this to fix it and also is there any way to check to find out?

suzuki-guy

Check your ground wiring up by the headlights. Also make sure there is no corrosion.

lukemoore646

ground is a good bet because with headlights on you remove the ground your blinkers backfeed through

suzuki-guy

He fixed it it was ground!

lukemoore646

how did you find out i didn't see it posted, i am always interested in wiring problems

suzuki-guy

He had another post on here saying he fixed it and he and I Pmed back and forth. The guys who had it before him had a bad crimp on the ground wires.

proud_sierra_driver

Thanks for posting that I got it fixed. Since I was talking to you about it I forgot to post here that I fixed it.

suzuki-guy

No problem!~