Inermittent Blower Operation

Help, It's HOT!!!! I have a 03 Trailblazer that started having problems yesterday with the blower. It's off and on, but been more off. The blower blows low,high or not at all when you have the fan on high. The connection to the motor itself is solid. Tonite I got the blower to work fine then I cut Ac off and then back on. The fan was blowing low but seemed to pick up speed to high, cut Ac back off and back on and Ac was blowing low, the 3rd time it would not blow at all. Don't believe that I have a bad connection as these test were done sitting in the drive. Could this be a bad motor? Thanks, Dave

Check for voltage to the blower motor. On high you should have 12 volts while trying to operate the motor. If not check for switch or wiring problems. If yes replace motor.

Another clue has now poped up. The blower continues to blow after the engine is cut off. The only way to stop this is to remove the fuse.

Replace the blower relay/resistor, behind the glove box mounted on the blower case, common problem.

Replace the blower relay/resistor, behind the glove box mounted on the blower case, common problem.

For regular resister, GM part # 89019100 $58.20 at dealer.
For automatic air,GM part # 89018778,it's a module.$127.00
My truck is an 03 Trailblazer LT with auto air.

This will fix the problem,very common, dealer says.

Thanks, Jimmy I picked up 89018778 and it was right at 100.00. This took care of my problem. Thanks Dave

Thanks. Those part #'s deserve a sticky. Lots of good stuff here does. I know, who the hell has time to pull it all together and post it? Someday maybe.