1998 sierra

[jasonl]

what would be the cause of my tailights not working when my head lights are on. the bulbs are good and the reverse light, brake light both work.all my fuses that i tested are good.

 

[Sam Chicklets]

Most likely you need to replace the headlight switch

 

[jasonl]

where is that switch located?

 

[knuckleheaf27]

its most likely the switch you use to turn on the headlights.....

 

[jasonl]

what im saying is, that controls the tail lights from coming on?

 

[Sam Chicklets]

It does control the tail lights as well

 

[jasonl]

thank you for your help!!