I'm not sure where best to put this.

My 2002 TB has 150,000 miles. Out of no where the heater blower stopped working. It was on, hesitated, came back, then went off and stayed there.

Blower won't come on for defrost, ac or heat.

I don't know where to start. I'd like to see if I can take care of this myself.

Any help will be greatly appreciated. It's getting cold in Mpls.

Mike

 

I should add, it worked in all blower speed settings prior to this problem. It has the auto climate control.

The blower fuse is ok. From what I have read we are down to the resistor pack or the blower motor. If this is right, how do I test it to determine which it is and then I need to know how to replace it. Thanks. Anybody with help for my problem will be a hero.

 

I wouldnt jump to the internals just yet. When was the last time the coolant system was flushed? Thermostat replaced? If you heater core gets clogged up with dexcool sludge or other gunk, you'll lose your heat. The intermittent heat at first is a good indicator that you have a clog/bubble stuck in the heater core.

Do you still have the original black plastic radiator cap on there? How does your coolant look?

 

I tried to respond to this earlier. But please be a little more patient when waiting for a response. If you feel you have information to add, please use the edit function to do so.

Yes, it most likely is the blower motor control module (not necessarily a resistor pack like the non-automatic equipped trucks have). The control module is in the same position as the resistor pack of a non-auto truck which is located under the passenger side of the dash behind the blower motor.

To test it, see below:




To replace it, you will need a small flat blade screwdriver, a 7mm nut driver or socket, a 7/32" nut driver or socket and possibly a flashlight. You will need to remove the passenger side hush panel from under the dash. Disconnect the main wiring harness, then remove the two 7/32" screws. Empty the glove box and find the metal tab that holds it from flipping out (towards the left side of the glove box under the edge of the dash). Move the tab and flip the glove box out of the way. Disconnect the electrical connection on the side of the blower motor. Plug the new (improved) resistor pack into the blower motor and close the glove box. Reinstall the mounting screws into the new resistor pack and plug in the main harness. Reinstall the hush panel and you are done.

The cooling system being low or even a plugged heater core will not prohibit the blower motor from functioning.

 

Sorry about the edit thing. I'll pay more attention.

I have the test steps you posted and I'll check it out. Might be easier to replace then to test, but I'll give it a try.

Thanks a heap!

 

Ohhh my apologies...I didnt notice you said LTZ...meaning the newer trailblazer

Good luck with the replacement!

 

Wolfpack is a funny guy.

I got to step 3 and get ~4 v reading in the low setting that increases with every increase in blower speed setting. I'm reading it off of the purple and black wires that connect to the blower motor.

If I'm doing this right, I'm guess'n that I need to replace the blower motor. If you agree, do you have a plan for replacing the motor without loosing a lot of blood?

 

I would say that confirms that the system is working properly.

Did you try reinstalling the connector into the blower motor? Did that do anything?

Have you tried hitting the blower motor with the handle of a screw driver to give it a jolt? Did it respond?

If both of those tests did nothing, then I would say that the blower motor is toast. As far as replacement goes, have a selection of nut drivers handy or a good 1/4" ratchet set with some decent length extensions to get your hands out of the tight spots. You have to remove the glove box completely and basically lay down on the floor board to see everything. Or you can grab yourself a mechanics mirror and have an easier time at it.

 

Job done! You ROCK! New blower motor $92.19 from Red Rooster Auto Parts. Inside old motor housing was a bunch of tiny leaves and twigs that must have made their way in through the fresh air inlet somehow. If they didn't cause the problem they sure didn't help it any.

The shroud that covered the old motor was a real hassle to put back in place so it is now in the box of spare parts and the new motor is still quieter than the old one.

I was able to leave the glove box in place. Saved a ton of time.

Awesome, absolutely awesome. Rock'on.
Have a great Thanksgiving and thank you for all of your help!

Mike

 

Glad to help! Yeah, the dropping of the glove box helps if you have larger hands or have trouble getting the power connector loose.

Glad you got it all fixed up. You did not happen to remove the debris and plug the original fan back in did you?