2007 trailblazer low beams not working fuses ck ok

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2007 trailblazer low beams not working fuses ck ok

Unread post by guest » Wed Apr 14, 2021 1:26 pm

2007 trailblazer SS day time lights & low beam not working checked & replaced bulbs ,fuses ok ? still no high beams lights work turn signals work is tere a relay some were bad !

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carriedi
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Location: Oregon

Re: 2007 trailblazer low beams not working fuses ck ok

Unread post by carriedi » Thu Apr 15, 2021 5:42 am

okay, so what Confuses me is what you say about the lights that work or not. You say dtr lights don't work and low beams not working. You replaced the bulbs and still not working. But then you say high beams still not working. So, is it that no headlight ever work? No low beams, no high beams and no DRL (daytime running lights)?

things to check: Fuses are in the underhood fuse box. they are marked LT LOW HDLP (FUSE 6), LT HIGH HDLP (FUSE #5), RT HI HDLP (FUSE #2), RT LOW HDLP (FUSE #3). Those fuses go to the headlight bulbs. They are after the high and the low beam relays in the same fuse box. There are fuses for the relays. Low beams = HDM (fuse #53 for the 4.2L engine and fuse #57 for the 5.3L and 6.0L engine). High beams = COILS (fuse #14 for 5.3L and 6.0L, and they don't show a fuse for the high beam relay for the 4.2L in my wiring diagram)

so, each beam has it's own fuse. If all the lights don't work, it would be strange that all the fuses would blow at the same time. I would check the headlight relays. The low beam relay is relay #46. the high beam relay is relay #43. both in the underhood fuse box. Do you know how to check the relays and what pins in the fuse box you need to check? Do you have a test light to check for powers and grounds in the fuse box? Have you put power to the headlight fuses and see if the headlight light up? they should come on if you put power to the high or low beam fuses because they are after the relay.

let me know if you're going to need more information into checking farther of if you found the problem with the information you got so far.

Your headlight switch doesn't power up your headlights. The switch sends a signal to the body control module and the body control module turns on the headlight relays. It gets a little complicated if you have to get farther into it. Using a bi-directional scanner to request the BCM turn on the high and low beams. Then see if the lights work under those commands. See if the BCM gets the headlight switch or not. Could be a bad switch. could be a bad BCM. could be wiring somewhere.

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