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Chevrolet TrailBlazer, SUV
#142 of 173 Re: Headlamp Driver Module [mfllngm]
Sep 09, 2011 (10:09 am)
Hi. I have a 2005 Chevy TB and my lights have been mysteriously shutting themselves off while I am driving down the road. I do not want to take to a dealer so I am hoping that doing what you did - replacing the relay. Have your lights continued working after thhis replacement? It is only my regular beams. The parking lights will continue to work and my brights will turn on. I just don't want to be driving at night and then my lights go out on me!
#143 of 173 Re: Headlamp Driver Module [emniha]
Sep 09, 2011 (11:47 am)
I've dealt with this myself for 3 years now. Originally I went out and bought a relay. However, I tried taking the old relay out and putting it back in several times (10-15 times) which in turn cleaned the relay and fuse box terminals. My old relay has worked fine for 3 years since this cleaning, however, just recently went out on me completely. When removing the relay, make sure it's not super hot. If it is, replace it. I always keep a spare relay in my glovebox in case I run across someone with this problem. My new relay has been working great and is much cooler than the old one. Sometimes the old relays solder joints on the inside of it will crack, causing arcing which will make it hot......just replace it. I expect that at some point in time that my new relay will stop working in due time (temporarily), but it will be years. Just needs to be cleaned, not sure why, but that relay oxidizes very easily, and is the most common problem with TB's. 3 years ago, I had to special order the part....NO ONE had it in stock. 3 years later, everyone has this in stock, it's that common.
On a side note, if your lights go out on you, just switch relay #45 and 46, your lights will start working again. But keep an eye on your temperature, the other one controls your fan. Like me, if you do need to switch relays, you're check engine light will eventually go on. Reason- there will be no communication for your fan to turn on and off. Which will throw an OBDII code (don't remember the #), but it's "lost communication with the fan" Just switch them back or replace the bad relay, the check engine light will go off automatically.
#144 of 173 Re: Headlamp Driver Module [fj4072]
Sep 10, 2011 (6:01 am)
This forum is so awesome I was about to spend $300 to have someone fix my lights. I have been experiencing the problem of both headlights low beam going out on me. I dont understand why. Please help me to understand what you are saying to do. Do I take 45 relay and put 46 in its spot? Do i need to leave something in 46 also? I am clearly not a mechanic and do not know where this is located but am willing to figure it out. Anything I can do to save some money will help. I appreciate your info.
#145 of 173 Re: Headlamp Driver Module [bigproblems33]
Sep 12, 2011 (7:42 am)
Yes, just switch the two relays to get you out of a jam. So #45, put in the #46 slot, and vis versa. Don't want to leave it too long or you'll get a check engine light for no communication to your fan. The fuse box under the hood, next to the battery is where they are located. The plastic cover has a schematic of the locations of the black colored relays, they are right next to each other. Buy a new relay, $40 from Autozone.
My explanation of "why" is a thread or two above yours. The 2 problems are basically oxidation of the terminals, and cracked solder joints in the relay itself. Enjoy your $260 you didn't have to spend!
Sep 15, 2011 (12:06 pm)
I have an 02 Trailblazer. I was lucky enough to get pulled over because my headlight was out. Thought no big deal. I ran up to Autozone the next day and bought a set. Replaced them and but of course, the drivers light is still out. I checked all the head light fuses and I didn't see any that were blown. I made sure the connection was tight and the connector itself seemed fine. I have no clue and I'm living off a student loan so I don't really have money to go to a shop and since I'm in a small town, that cop will probably ticket me next time! Any advice would be GREATLY APPRECIATED. Once again, thank you.
#147 of 173 Re: HELP!!! [deltajoel]
Sep 15, 2011 (12:28 pm)
When it comes to individual lights not working, count the relay problem out.
There is a known problem with the connector itself melting on the inside. Have you checked this out, or is that connector getting power? Hook a meter to it and see if you get power. Many people have needed to buy that pigtail and replace with a high heat ceramic connector. The wires going to the connector are too small for the amount of heat that goes to it. Which is why I use standard bulbs, not the extra brights ones you can buy, which draw more heat. On a side note, (just in case you don't know), you cannot touch the bulb itself with bare hands, the oil from your hands will burn a hole in that bulb really quick. Another thing to check, try switching bulbs from the one that works.
#148 of 173 Headlight Problem
Oct 06, 2011 (2:28 pm)
I have a 2005 ext-ls, I also had the problem with the headlights going out. I switched #45 and #46 relays and they worked fine, I bought a new relay at Advanced Auto for 34.99 and tax. Also my rear stereo speakers and cruise control were not working and the new relay fixed that problem as well (strange but they must be connected somehow). I will mention that my check engine light came on and the codes were for the fan cluch, fan cluch sensor and oxygen sensor, I replaced all and added a k&n cold air intake new plugs and cleaned the throttle body and mass air flow sensor, (the throttle body clean is apparently a necessity with the l6 every year or 20k miles) I mention the fan and cluch because I bought the truck used and suspect the dealer swapped the relays and reset the check engine light this caused the fan cluch and sensor to get defective 2 months after the purchase.
Next question- after installing the new parts I reset the check engine light. During the first drive it came back on, Advanced Auto says the only code its throwing out is for the mass air sensor is detecting cold air. I susspect its the new intake, is this normal?
Thanks for all the great info on this site!!!!!!!!!!!!
#149 of 173 Re: Headlight Problem [gator33]
Oct 06, 2011 (3:01 pm)
FYI, when ever you have a check engine light, the cruise control is disabled which is normal. When the light is reset or goes out, it will work again. Never heard of the rear speaker going out like that. When you switch relay #45 and #46, you will get a check engine light either immediately or shortly after the switch, this is normal. The other relay runs the fan clutch operation, so that's what that is (happened to me also). The oxygen sensor, must of been coinsidence that it was going bad. Yes clean that Throttle body puppy once a year or more often if needed. Really no good way to clean our MAS , buy a new one, cleaning doesn't seem to work for us.
As for your last question, having a new MAS MAY solve that light, however, I'd call K&N myself. They have an awesome technical department that could answer your question.
#150 of 173 2006 Trailblazer headlights
Nov 16, 2011 (1:26 pm)
I wish I had found this forum sooner; I have a feeling it would have saved me some $. My daughter has a 2006 Trailblazer and the low beams suddenly stopped working. Took it to a mechanic who at first thought it was a switch, then decided it was the body control module. So, $500 later, we have low beams. My question is this---Is the BCM where the relays are? It seems like relays are the popular choice here for fixing the problem...I probably got hosed for my $500, but I couldn't have her driving around with her high beams on. Any advice?
#151 of 173 Re: 2006 Trailblazer headlights [vskardainreno]
Nov 16, 2011 (2:05 pm)
No, the relays are in the fuse box. The BCM (Body Control Module) doesn't have anything to do with the low beam headlights.
This relay problem can and IS intermittent. So if the relay itself wasn't taken out and or either replaced or cleaned, your low beam lights will eventually go out again. I would ask if this was done. If not, I'd encourage you to replace it yourself. It's about $40 or less, the fuse box is located right next to the battery on the drivers side. Take the top off the fuse box, then take the plastic piece off too. Both just pull up, no tools needed. Look at the bottom of the cover and look at either #43 or #46 relay, it's one of these two. They are both right next to each other, I believe it's the one closest to the firewall. Pull it up and out and replace. Will take ya 15 seconds to do. Good luck!