Check engine light comes on goes off randomly. Head lights sometimes brighten and dim, recently the vehicle Stalled in const. Zone when I slowed down while headlights were bright and dimming. Restarted right away, ??? Seemed fine, then several trips later stalled at traffic light while bright and dimming. All other times fine. Check engine light can be on or off, seems to come on then go off later for no apparent reason. (Nothing changed, just started and stopped). Mech put on computer, says nothing wrong. No codes.???

i just replaced the alternator, idler pully, and spark plugs. at the cost of $250 bucks or so. the car ran fricken fantastic!!! for about 12 hours. then the lights intermittently dim and it sounds like there's a misfire, sometimes it makes it feel like the tranny is going out. the owners manual says that when the lights flash or dim it means the electrical system is overloading. well GM??? why don't you take some of that bailout money and figure out the problem and then fix our cars that you sold to us. i guess if GM gave a damn then they wouldn't have had to be bailed out in the first place.

My lights dim and flicker along with the dash board instrumentation and the volt meter dips down to around 12. This problem initially occurred about a year and a half ago but the alternator went up only a few days later. I replaced the alternator and battery. With the replacement of the alternator the problem disappeared so i naturally assumed the issues were related. The issue has returned and is worse than ever!! It seems to have some sort of short. I called my local auto shop who said he would take a look but doubted he would find the problem since he couldn't with the last one he looked at!! I really enjoy this vehicle and i'm hoping that someone stumbles across the real issue and is able to help me to fix my trailblazer.

when I am driving my headlights flicker and dim. I took it in to have it checked and the mechanic told me that it was the alternator. I took it to a Chevy dealer to have a second opinion and they said that the alternator was fine, but the water pump was bad. Of course this is after the warranty is out!! Still having the problem, I took it to a different mechanic and they hooked it up the diagnostic machine and they can not find anything wrong. My car is still doing this!!!!! I didn't know about a recall on this until I was talking to my brother this past weekend and I am pissed the Chevy did not put something out about this!!!!! They should take back all of our 2005 Trailblazers (worst model year made)!!!!! RIDICULOUS~~

The lights flash. I noticed this while it was still under warranty. I took it to the dealer, he said you can't turn off the engine because the computer resets. So I took it straight to the dealer when it happened only for them to tell me, in essence, I'm crazy! There is no code being pulled on the computer. After replacing the alternator and other items suggested by the car dealership where I purchased this vehicle, this problem continues. We even contacted General Motors and they, again, in not these exact words, said sorry for your luck! They know this problem exists. I didn't wait. My vehicle was still under warranty. My vehicle was a "dealer" vehicle. I approached the dealership about the lemon law and was told this vehicle didn't qualify because it didn't pull a code. This mainly occurs in the fall, winter, and spring. And, to top it off, I was so aggravated, I went to trade it in and they (Chevrolet dealers) were not willing to give me anything for it!

I hate this problem! I finally go get a car off the lot for the first time, only one previous owner, and I have a problem that they can't fix. I've brought it in for this dimming problem, and they changed out a belt...which helped for like 3 days. Funny huh! Now, after reading all of the other info on this website, I realize it may not GET fixed. Talk about a waste of money and a disappointment. To boot,...the 2005 was the one with the most complaints on here! geesh. I learned my lesson to check on here before buying another car. I'll let ya know if it actually gets fixed! This problem makes me feel like my car could stop working at any moment, especially in cold weather...and in the dark. Not secure!!

When I first noticed this problem I had just purchased the Auto used with about 33000 miles on it. I read the CarFax report, which stated they had a problem of this type and that the dealer had replaced the Alternator to correct the problem. Having worked on cars most of my life I figured this was a possible new car problem and dismissed it as being fixed. At about 38000 miles, I saw the lights blinking and had it into the service center and they kept it for 3 days and said they could not find anything wrong (Loose connections, bad Alternator, Etc..) and the problem seemed to be corrected. At 45000 miles the problem is back and becoming more frequent.

It seem to be more noticeable in Winter months and when I am accelerating up a hill above 35MPH and take my foot off the gas. All lights on the vehicle dim and come back bright and the Battery charge indicator will dip from 14.2 Volts down to 12 Volts and climb back up. If I put my foot back on the gas it will climb quicker under acceleration than if I am just coasting but either way it will recover. Sometimes I can make it happen 2 to 3 times in a row by accelerating above 35MPH and then decelerating again. But this does not happen every time.

I am an EE and have seen this kind of reaction it what is called a PolyFuse. This is a kind of fuse that when it goes over current will open like a regular fuse and is supposed to stay open for a few minutes or as long as the over current condition exists. But in my experience, if the current rating of the PolyFuse is to close to the total current rating the unit will only open for a few milliseconds, like turning a light switch off and on.

I do not know if the auto industry has changed the Fuseable Links within the wire harness of the vehicles into this kind of technology. And if they have I would think that it would be showing up on more vehicles than this and I do not know that it is not. But I think it may be worth looking into.

As soon as I hit 50k on the Trailblazer, this problem started happening. The entire electrical system - headlights, dash, radio/clock, etc. dim and come back up. The engine RPM's also drop, though I still am able to accelerate to correct that. Basically it seems the whole car just starts to die then comes back. This happens in a rapid succession, anywhere from a few times and then clears, to the whole time I am driving (most logged time is 30 minutes). I took it in to a Chevy dealership back in October of 07 when it first started, and it was in the shop for 3 weeks. The best explanation I got was a loose bolt (which apparently required them to disassemble then reassemble the whole engine - over $3k in work if I didn't have the extended warranty - WHEW!). As I'm not particularly mechanically inclined, I can't swear as to the validity of that diagnosis...but whatever they did, didn't work. I still have the problem from time to time and notice it more in cold weather. I'm just biding my time until I can afford to switch, hoping it doesn't blow up on me in the mean time!