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Chevrolet TrailBlazer Maintenance and Repair



  • My 04 trailblazers service engine soon light flickers on ocass while coasting between 30-45 mph. Also if I brake in between those speeds the abs breaks feel like they come on and the service engine soon light comes back on.
    This has happened since I bought it brand new. The service dept's computer says nothing is wrong, and it will not "assimilate" for them! help!
  • Any luck with the service engine soon light? what exactly did it do? mine flickers on between 35- 45 mph while coasting. and if I brake in between these speeds the abs brakes come on and the light flickers again.
  • "You might check to see if your hood is rattling. Mine did this and the dealer found my hood was not quite resting correctly when closed. Dealer made a few adjustments and it was fixed, and have not had any problems since. Let us know. "
  • I just baught a 2005 TB EXT LS and the owners manual says to change the Transmission fluid and filter every 50,000 - 100,000 and 150,000.
  • deano9deano9 Posts: 1
    I have an '02 Trailblazer with 100,000 miles on it. Just wondering if anyone out there has had a tune-up yet. If it's running fine, do I really need to change the spark plugs?
  • :confuse:
    I am having an electrical problem of sorts with my new 2005 TB LS. When I decelerate or go down a hill without pressing the accelerator my headlights flicker on and off. Sometimes the gauge lights will also flicker, but not as frequently as the headlights. After an hour or so of driving this tends to go away. I have also noticed this problem under some acceleration conditions as well. This troubled me greatly and gone as far as to take it in to have it checked.

    The Dealer did a full battery test and concluded NOTHING was wrong! However, they did say that similar problems have been reported in other Chevy/GM products, most notably the Hummer. They gave me a TSB and indicated that the problem was likely the on-board computer was unable to properly adjust voltage.

    Anyone else out there experience this problem with the TB or other GM vehicles? Anyone know of any solutions to this problem?

    This has me GREATLY worried as at night it appears I am turning my lights on and off!

  • I've had the same problems out of my 2005 TrailBlazer. The lights and guages flicker when breaking, coasting and sometimes accelerating. Also I've had problems with my ABS and Check Engine Light coming on when Driving short distances. It feels as if the ABS kicks in quite often when hitting the breaks. Most of the time this is when my lights and guages flicker.

    I have taken mine into the dealership 2 times now. They have changed my alternator both times, checked my computer system and my breaks, they say nothing is wrong, but the problems still continue. Someone told me that maybe I should look into having a high output alternator installed by the dealership. This may eliminate these problems. Does anyone else have any suggestions? Please email me at if you do.
  • I too am having this same problem with my 2005 TB. My instrument lights and head lights flicker dim to bright. It happened in Oct 05 and we took it in and were told there wasn't anything wrong. It happened again last Sat. and we took it in and were told once again that there is nothing wrong. It's going up to the dealership today again for them to look at. I have done some research and see several forums with people complaining about this but I have not found anyone with a solution. I was told that they absolutely will not change out parts unless their diagnostic computer tells them there is a specific issue. I feel ripped off because I have a brand new car I debate driving-I am always leary of driving at night now. Any solutions or possible answers?
  • gmfangmfan Posts: 188
    If I was in your shoes, I would change the drive belt, change the tranny fluid and filter, and go ahead and do the spark plugs. You might consider doing a coolant/anti-freeze flush also.

    That is all I would do.
  • jennmwjennmw Posts: 5
    Has anyone had this problem? It worked a couple months ago but when we tried it this weekend the lights didn't come on and we didn't feel it go into 4 wheel drive in either hi or lo.
  • Hi, just a week ago purchased an '05 Trailblazer...was wondering if the sound I am hearing when starting and during shut-off is normal - comes from the instrument panel, sounds like a compressor letting out air - that's about the best way I can describe it, all the gauge markers go back to the left position while this sound is happening, makes this sound upon starting also, is this normal? Thanks for ANY possible help, until I can get back to the dealer, I need some reassurance I guess. :cry:
  • You can change the Trans Fluid every 5000 miles and it will not matter. The Sun Gears in the trans are junk.

    When you get into traffic on a summer day you will see your water temp go up to as high as 230 if the A/C is on. The dealer will tell you that is not a problem and the motor can run at 240. The motor may handle that temp but the sun gear in the trans will not.
  • I have an 02 Trailblazer. I had this system worked on last July when air from heat and A/C would only work though the defrost and not the dash vents or floor.

    When I had it worked on. They tore my dash apart and said the arms that work the vents were made of plastic and had broken. They said they had to have the system reset by a GM Dealer. Cost over $700.00 dollars.

    The problem has started all over. Air though defrost and very little though dash vents, none though floor. The system in the back of SUV works OK.

    Remember the good old days when this Kind of stuff never broke?

    Any ideas on a possible reset?
  • iavantiavant Posts: 1
    I have a 2004 Trailblazer. Its been in the shop several times already for the check engine soon light.They replace the sensor, injection pump w/Relay and relay and 02 sensor and the light came back on after a one day. had anyone had the same problem I had to drop the truck back off to the dealer again to try to get it fixed
  • daleb2daleb2 Posts: 8
    Same thing is happening here on a 2005 TB LS just started the other day. There are recent complaints at the NHTSA (Government) about this problem with both the Trailblazer and Envoy
  • I have been having the same exact problem with my headlights and gauges flickering and dimming in my new 2005 TB LS. This has been going on for the past 5 months and I have had the car for only 6 months. The dealership has been trying to find the problem but it will not do it for them. I have been stopped by the police 2 times for driving with faulty equipment. If anyone has any answers that may help me out that would be great.
  • I also Have a 2002 trailblazer and the 4x4 is not working. Have you taken it to a shop yet?
  • jennmwjennmw Posts: 5
    Nope, not yet, you?
  • lagelage Posts: 5
    I have had this problem a few times. They replaced the switch once. The other 2 tiomes the computer lost its memory and the dealer had to reprogram it. GM has a problem in this area of the trailblazer.
  • lagelage Posts: 5
    I have a 2003 4 x 4 Trailblazer with the 4.2L engine. At 45,000 KM the engine started using oil. It was using a liter every 1,100 KM. The dealer replaced the piston rings but no change. They finally had to put a new cylinder head on it and it is fine now. They told me that 2 valve guides were scored letting oil into the engine. For the record the oil is changed by the dealer every 5,000 KM. I now have 100,000 KM on it and it runs good. No other major problems except a rattle noise in front suspension when going over rough surfaces. I had to replace the sway links in the front suspension. They were worn out. They need a grease nipple on them GM engineers!
  • lagelage Posts: 5
    Make sure your gas cap is tight.
  • lagelage Posts: 5
    You neeed to replace the sway links. they are worn out.
  • My sister owns a 04 TB that has the same dimming issue. Here's what I have found from a good friend that's a top notch tech: Its very common he says and the correct is simple, they have upgraded the alt... and the problem has not happened since.He said its a diode that has gone bad.
  • gmfangmfan Posts: 188
    There were posts on the earlier models that had experienced this same problem you describle. My 02 has done it since day one...I never took it back to the dealer since mine is not that bad. I believe it is the tachometer instrument cluster...try this, while the car is in idle, turn radio and fan off, and race the engine to 1300 rpms...if the noise changes, it is the tachometer. I always drive with the fan on postion #1 and it drowns out the noise. Dealer should be aware of this problem since several on this forum have posted free replacement when done under 3/36 warranty. Let us know.

  • Wow!I am new here but looks like the problems with the TB aren't.My wifes '04 TB keeps throwing DTC P0410,which is secondary air injection.I replaced the sensors on the exhaust and cat,had code erased and few days later back on.Replaced the relay for the air pump and one in the fuse box in engine compartment.A day later,back on again.Anyone have this or similar problem?Also,now we are also getting the lights dimming and amp gauge dips.I read somewhere that it could be a diode in the alternator going bad and that they have a upgraded alt.I will have a shop check mine and see if it is that.
  • I just had to change the switch on my 03 EXT 4X4 ($130.00) because it would switch in and out of 4 wheel drive. Perhaps that is the problem.
  • I have a 02 TB. Several times the instrument panel has just gone out. It comes back alive after waiting to start again for a while. Now, I hear 3-4 loud clicking noises right after the engine starts. It sounds like it is coming from inside the dash around the defroster vent area. Has anyone experienced this before. Of course, the warranty has been out for quite a while. :confuse:
  • burdawgburdawg Posts: 1,524
    That clicking noise you hear is the mode door actuator. There's a replacement part and procedure (special puller tool) to replace it without taking the dash apart. We just had it done on our 02 under our GMPP plan after putting up with it for some time. I don't have the link but there's a short article in GM Tech Link that describes it.
  • My 02 TB has a terrible squeaking from the belt area but when I turn the steering wheel it stops. Is there any way to fix this without replacing the whole power steering pump and pulley. :confuse:
  • For those whose headlights and interior lights flicker for apparently no reason while driving, try letting your truck idle for 20 seconds before driving. On the 04 and 05s with the I6 engine there is a pollution control device called a Secondary Air Injection pump.

    Every time you start your car it runs diagnostic checks on this system. First it runs a "passive" test. If it passes the test, it stops testing. If it fails the passive test it runs an "active" test. Apparently this active test draws quite a bit of juice threrefore the lights flicker.

    By letting the truck idle for 20 seconds before driving away it should allow the passive test to pass. According to TSB 05-08-42-001 this should work 99% of the time.

    The light flickering drove me nuts the one time it happend to me!
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