08 gmc sierra denali tail light problem

[Daniel Kleich]

Hey I have a 08 GMC sierra 1500 Denali and I’m having problems with the driver side tail light not working properly I turn on my left blinker and it blinks three times normal than starts to hyperflash , and they are not LED’s. The running lights work but the blinker, the brake light, and reverse light do not turn on at all, I have checked fuses and relays replaced the bulbs, replaced the left tail light harness and replaced the tail light junction block and nothing seems to be working

[Jsdirt]

Sounds like a low voltage or bad ground issue.  Connect a set of jumper cables to just the ground on the battery, connect a length of wire to whichever side is grounded, then stick a pin into the ground terminal of any of the non-operative lights & connect the wire to that. If everything suddenly works, you've got a bad ground. Make sure the pin is making contact - sometimes they won't when you think they are, and that'll skew your test.

 

You'll need a meter to see if you're getting battery voltage, or close to it, to the lights as well if the ground circuit checks out. 

Edited August 26, 2023 by Jsdirt