what causes the dim lights to go on and off ?

a bad ground. Follow the negative battery cable from the terminal down to the chassis and engine...make 'em all sparky fresh and clean, put 'em back together and this "dimming" will go away.

Sometimes my dim lights will work and sometimes they go out going down the road and they flicker off and on while sitting still.

oh the low beam headlights. you had me thinking some sort of light was dim, if included headlights in your question that would have been better.

If you're talking low beams, they are on a circuit breaker instead of a fuse. You could be drawing too many amps, tripping the breaker and it comes back on when it resets.

we still dunno what lights your talking about. Is this the guessing game?

dirty potentiometer or rheostat~

kbro, think he's talkin' about the dash lights seeing as he's unresponsive to anything responsible~

Aint no telling judgy. hey I just noticed he have a new #1 Guru.

H25....mellow fellow....will back him on everything he says!

I have a 2006 trailblazer and it does the same thing, the dim lights just go off, they may stay off 5 minutes or 5 hours.... we have changed All of the relays and fuses and replaced the bulbs, I am scared to be out at night because of it. The brights still work, but people get real upset with me!!

the BCM body control module has a mind of it's own and frankly, those who have them wish they could turn them off, sure there's gotta be a way, involving the terms "menu" and "select" and plenty of beep beep this and that membrane switch activation what has you feeling as confident as standing in a pool of ankle-deep chicken stock~

the mini has two pages on what you can do with the three buttons on the key controller and is a pain in the gazooka~

Sounds a lot like the same problem I had w/my 2006 Trailblazer. The headlights went completely out while I was driving. Can't remember if I had hi or low beams on. I tried to switch back & fourth between hi & low but still no lights. My dimmer switch is on the same arm as my turn signals & cruise control (off of the steering column). Flicking it forward turns on hi beam, flicking back turns on low beam. Not exactly sure what it does if I pull it back past the low beam slot & hold it. The lights did come on when I did that but they were brighter than the normal hi beams (could it have turned on both low & hi beam headlights @ the same time?). When I let go the headlights went back out again. While I was pulled off the road waiting, they suddenly came back on w/me doing nothing. It has ~130,000 miles on it. It had ~85,000 when I bought it. It did this a few months ago, never did it before & hasn't since but then I also pretty much quit driving it @ night. Is there something simple enough that I can do to fix it or does if require taking it to a licensed mechanic?

will check into the existence of a headlight relay...gonna have to find your schematic.~

2007 Chevy Trailblazer: This morning (early hours in the dark), my headlights (standard, not hi-beam) started flickering and then went out and then came on again and then flickered again and went out and stayed out....while I was on the interstate. Scary! All other lights work, parking lights, tail lights, dashlights, etc. Would a bad relay/fuse cause the lights to flicker first before they go out or should I take it to have the electrical checked out?

Thank you tennisshoes. I almost wasted money on a new relay. Good thing I saw this first. I will see if I can find somewhere to take it. Thanks again!

Recall on Dim Lights since 2015. Trailblazers...

Ugh! Headlights randomly coming on and off. It's possessed. Lol. Changed out Combo switch, still happening. Code B0951, 2003 Chevy Trailblazer.

Pretty good for a lady, they tried to charge me $100 labor. Easy snap on and off. Just wish it would have fixed problem. On to next possible fix, relay.