This 2003 Chevrolet Trailblazer came in with the complaint that the blower would not work on any speed and that the Brake and ABS lights stay on. Since I have seen this problem before, I knew right where to go to test. then ignition switch. The first thing that has to be done is to remove the tilt lever handle. Some just pull straight out but this one was a little difficult so I used a screwdriver for leverage.
After the lever is pulled past the detent it comes out easily the rest of the way.
Now the trim panels under the dash have to come out. Two screws, 7mm, for the black hush panel under the dash.
With the black panel down there are two screws that hold the bottom of the knee bolster panel.
Two at the top of the panel.
Then the panel will unsnap. Someone has already been here. The spring clips are missing.
Now there is a soft piece of rubber trim at the rear of the lower cover. It needs to be worked loose of the lower cover. Then carefully unsnap the lower cover and work it loose from the column and the soft rubber piece in the rear. Some models may require removing the steering wheel to get the cover off and some may have screws in the underside of the lower cover.
Now that the switch wiring is exposed. Check for constant battery power on the red wire as shown below.
Turn the ignition on and check for power on the orange wire. We have just diagnosed a faulty ignition switch.
To remove the switch, I first gently pulled the wiring for the key buzzer and /or antitheft antenna out of the retainer as shown below.
There is a special GM tool for releasing the ignition switch retainers but I just use a couple of pocket screwdrivers. There are two white spring loaded pins that have to be pushed in to allow the switch to come out.
You can now see the two pins exposed as I pulled the switch down.
GM says to remove the lock cylinder and use a tool to fully rotate the inner mechanism but I don’t bother. I just make sure the ignition is off. Key out. Pull the switch down and note the position of the gear teeth. DO NOT rotate the gear teeth. Adjust the teeth on the new switch to match the old switch position.
The wiring harness lock is a little difficult to release. You are supposed to depress the locking tab.
I was having a problem so wedged my screwdriver between the switch housing and lifted it instead. If something breaks, I would rather break an old part that is being replaced, instead of the latch on the harness connector. Makes sense, right?
I checked the harness connector for damage and all was okay.
Maybe a better view of the plug in connection to the switch.
I adjusted the gear teeth to the same position. I also compared them one behind the other to check the alignment.
The new switch on the right with the gray cover. To purchase the new updated ignition switch please click here.
Slide the new switch into place until the spring loaded locking tabs click into place.
Plug the wiring harness back up to the switch. Positioned the rest of the wiring back into the retainer on the side of the switch.
Cranked the engine and checked the blower and all is well. Time to finish installing the rest of the parts.
To see the video for this repair please click here.
This ignition switch fits the following vehicles, however the repair procedure may vary between these vehicles.
2001-2005 Pontiac Aztek
2002-2004 Oldsmobile Bravada
2002-2007 Buick Rendezvous
2002-2009 Chevrolet Trailblazer
2002-2009 GMC Envoy
2003-2006 Cadillac Escalade
2003-2006 Chevrolet SSR
2003-2006 Chevrolet Suburban
2003-2006 GMC Savana
2003-2006 GMC Yukon
2003-2007 Chevrolet Silverado
2003-2007 Chevrolet Express
2003-2007 GMC Sierra
2003-2007 Hummer H2
2003-2008 Isuzu Ascender
2004-2006 Chevrolet Tahoe
2005-2007 Buick Rainier
2006 Chevrolet Avalanche
2006-2009 Saab 9-7X
Hi Sparky, I had my ignition starter switch replaced by a local mechanic. The car ran fine until I cut the air on and nothing came out, then the abs and brake lights came on with the dinging sound. What should I do next?
Check basic battery voltage and cable connections. Check the security light in the instrument cluster to see what it is doing. Flashing or on steady would point towards a security issue. Check voltage on fuse #17,crank fuse in the underhood fuse box while the ignition is in the crank position. Check the starter relay, #47 in the underhood fuse box. If all are okay you may have a faulty starter.
i have a 2003 Chevy Trailblazer Lt with e 5.3 in it starts fine no lights on in dash blower works but you may stop and go in a store and when you try to start all light come on in dash but want crank you can keep cycling the key and it will finally start… I need help Please..
I have a 2004 Silverado that had the same symptoms. Abs and brake light on with no cabin hvac blower… I light tested the orange wire from the ignitition switch and it was dead. I went to my local auto parts picked up a new switch, followed your instructions on removal and replacement. changed it out and solved my problem in 15 minutes. (the one my mechanic told me was for sure the blower module)…
Thanks for the info Sparky!! You’re helping the masses, keep up the great info,let me know if I can ever help you with a home constuction problem.
Thanks again,
A California building contractor
Please go to the “Sparky’s Repair Article Menu” tab near the top left of the page. Under “GM Full Sized Trucks & SUV’s” find “HVAC Front”, “Blower Issues” & “Manual Controls”. There you will find three articles for 1997 GMC that should give you all the information you should need to check your blower issue. I am not sure if the ABS problem will be related to the blower issues in your year model truck.