2008 Chevrolet Trailblazer Low Beam HeadLights

Tiny
SIRJR
  • MEMBER
  • 2008 CHEVROLET TRAILBLAZER
  • 53,000 MILES
In the Spring, while I was driving the vehicle, the headlights (both) cut out. The next day they worked fine. Since that time, this has happened about two additional times. Yesterday, the headlights have stopped working. This is the base SS model with the dashboard headlamp control settings of: OFF, AUTOMATIC DRL/AHS, PARKING LAMPS, HEADLAMPS. The low beam headlamps do not work in any of the settings. All the other lights work on the vehicle including the high beams and fog/driving lights.
Help! Please direct me on how I go about resolving this problem. Thank you.
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Friday, September 27th, 2013 AT 6:27 PM

12 Replies

Tiny
SATURNTECH9
  • EXPERT
Do you have a multi meter to do some testing?Also it would really help if the vechile was scanned for codes with a professional scan tool that can read codes in all the computers. Also let me know all the exact code numbers you have not code descriptions?
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Friday, September 27th, 2013 AT 6:49 PM
Tiny
SIRJR
  • MEMBER
I have a multi-meter. I also have a Actron AutoScanner. Although it is not a professional model, it is a scanner and code reader. I will scan/read the vehicle today to see if any codes are listed. There are no indicators that have illuminated on the dash.
Thanks for the response.
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Saturday, September 28th, 2013 AT 6:46 AM
Tiny
SATURNTECH9
  • EXPERT
Your scanner will only read engine codes and some of the transmission codes. You need a scan tool that can reqd the body control and all the other computer's in your vechile. Unfornately the newer the vechile the more computers you have. They have codes for everything on the newer cars turn signals etc. That's why I say get a professional scan tool to scan all the computers in your car. Also sometimes it takes those scan tools to diagnose the problem even. Make sure you get the exact code numbers. Makes it more difficult to diagnose also.
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Saturday, September 28th, 2013 AT 7:29 AM
Tiny
SIRJR
  • MEMBER
My unit is a Actron CP9145. It did not show any issues.

By a professional scan, am I able to get this done at a auto parts store or do I have to go to a mechanic/dealer?
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Saturday, September 28th, 2013 AT 8:50 AM
Tiny
SATURNTECH9
  • EXPERT
Your scan tool can only read engine and transmissioncodes also the same with the auto parts store.A ddealer or shop would have the real expensive scan tool that can read all the different computers codes. Let's start with the multi meter and see share it leads. Let's start by turning on the low beams and see what were missing at the low beam bulb connector power or ground?
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Saturday, September 28th, 2013 AT 1:15 PM
Tiny
SIRJR
  • MEMBER
Another bit of strange information for you. I was told by a neighbor to take out the relay and put it back in regarding a possible contact issue. In the engine compartment, I removed the cover from the fuse/relay box. The schematic on the underside of the cover stated the relay for the low beam lights & wipers should be in position #37; however, there was no relay in that slot. The windshield wipers work fine. Does this make any sense to you?

As soon as I can do the diagnostics on the low beams I will get back to you. We're supposed to get a lot of rain shortly, so I do not know when I can start.

Thank you.
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Saturday, September 28th, 2013 AT 2:06 PM
Tiny
SATURNTECH9
  • EXPERT
Relay number 46 labeled HDM RELAY also fuse number 6 and fuse number 3 feeds power to the low beam bulbs. This is all in the under hood fuse box.
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Saturday, September 28th, 2013 AT 3:48 PM
Tiny
SATURNTECH9
  • EXPERT
Also fuse number 57 feeds power to the the bcm relay.
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Saturday, September 28th, 2013 AT 3:49 PM
Tiny
SIRJR
  • MEMBER
Thank you for the additional information. What does "bcm" stand for?

Update: In order to access the bulbs and connections, by removing the headlight housing, the grill has to be removed. I was able to remove all this and put the headlight housings back on the vehicle before dark. I did not have any time to do testing. When I did a head light check, now the high beams do not work either except in the flash mode. They did work prior to the removal and re installation of the headlight housings. Does this give you any additional clues?
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Saturday, September 28th, 2013 AT 4:43 PM
Tiny
SATURNTECH9
  • EXPERT
Sorry about the bcm that was a mistake I ment to say hdm relay feed for the number 57 fuse. Also what don't you have to the bulbs power or ground?You may have a loose connection if the high beams don't work now that you moved the wires around.
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Saturday, September 28th, 2013 AT 4:53 PM
Tiny
SIRJR
  • MEMBER
Replaced relay # 46 HDM.

Problem solved.
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Thursday, October 3rd, 2013 AT 7:50 PM
Tiny
SATURNTECH9
  • EXPERT
Glad to hear you got it fixed that's what we like to. Hear
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Thursday, October 3rd, 2013 AT 8:36 PM

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