Brake Light Issues

[Btheblue]

OK - my Tahoe has a brake issue I can't figure out. Bake lights work fine when lights off. When lights on, 3rd brake works but both brake taillights do not. If i pull one brake bulb the other light works fine. tried with 3 bulb on each side same results. Also, rear hazard lights to not flash with light on or off and turn signals work fine until you turn the lights on at which point the instrument cluster indicators flash double-time and rear lights occasionally flash and are dim. I have checked all fuses. Also note that the instrument cluster is bad, typical for these years and I'll be sending in to be repaired soon. Ideas?

Cool site BTW, has help me a lot with the Tahoe.

 

[Btheblue]

All grounds appear fine. I do use the trailer plug on occasion but pigtail and socket look fine. Now I'm wondering if it could just be the tail light circuit board? Do those go bad? Looks like simple fix and relatively inexpensive part.

 

[Dbowl]

I had a similar issue on mine w/ brake lights. I replaced the board you're referring to and the turn signal switch.

Worked fine after.

Friend of mine had the board laying around so we just did it at the same time. Not sure which actually solved the issue.

 

[Btheblue]

Come to think of it my turn signals started having issues first so I'll try that first, thx.

 

[Btheblue]

I replaced the turn signal switch still have the problem. Board is next, then the flasher relay.

 

[Btheblue]

Instrument cluster sent in to spedometerguy for rebuild, now installed, works great. I had no idea how easy and inexpensive this was to repair. About $75 with shipping.

Brake/blinker/flasher issue fixed by replacing tail light PC board. $30 and easy.