Running Lights at night. 2008 Chevy TrailBlazer.

iluminacca

I have a 2008 Trailblazer, the running lights work fine all day when driving, at night the lights go on, but after a while they just go off, leaving me with the only option of using my high beams, a friend told me his wife's trailblazer does the same thing, he replaced both the light control, and the multi purpose switch in the steering column and it still has the problem... so before I tear the dashboard apart, I'm wondering if its the light/darkness sensor?..or something else?

imidazol97

@iluminacca said:
I'm wondering if its the light/darkness sensor?..or something else?

These light control systems are difficult to check for us shadetree mechanics. I suspect if you keep reading and searching on the net, you'll find a forum where someone has fixed the same problem. I see there's a light control relay next to the headlight fuse in the under hood fuse/relay center. Is that the part you replaced?

Because these systems involve varied computer controls, you have to diagnose. I suggest going to your public library and seeing if they have AllData available on their computers as part of their databases. Ours does. While most databases can be accessed from my home computer using my library card number, the AllData can only be accessed at the library branch because AllData charges per computer which can access their data for the bulk user. However I have gone in with a CD and thumbdrive and copied the webpage and other diagrams that AllData had onto the CD/thumbdrive. It depends on how the computers are secured at your library. Or someone you know may have the AllData membership who can access your year and model. What you're after is the diagnosis flow chart that says if headlights don't work at night... check this, then this, etc..

You can check the light sensor by covering it with a piece of duct tape. That would be the same as having night time. If the low beams turn off after a while, then you've narrowed your problem.

Because the low beams stay on for a while, it sounds like it might be a relay or a control module that's warming up and failing.

What happens if you turn the headlights on low beam manually using the switch, bypassing the sun sensor?

iluminacca

Thanks for the reply...
"What happens if you turn the headlights on low beam manually using the switch, bypassing the sun sensor?"...If the lights go off....then no position on the switch turns them back on...I then resort to using only the high beams..btw..last night they stayed on with no problems.