Slow to spin up AC blower

emedlin

Well-Known Member
Seems my old 04 XUV is getting slow in its age. My HVAC has the manually and auto controls. When I turn on the AC very little air comes out. I have to put my hand on it to feel anything. After about 5 minutes or so I can feel the air on my face. It doesn't matter if I turn it all the way up or set it to auto. Once it gets up to speed if I manually turn it down then after to slows down turn it back up it will take another 5 minutes or so to spin up to full speed. Also when I turn the truck off, take the key out, and open the door the AC still blows for a good 30 seconds. I don't remember it doing that before.

How do I go about diagnosing the problem? Truck has 200k+ miles on it. So, I am assuming the blower motor or something is dying. Videos of diagnosing and fixing are appreciated.
 

Maverick6587

Silver Supporter
That sounds to me like your blower control module may be bad/going bad. I attached a few video links below to help with your testing. You'll need a multimeter for the testing.

link> Blower Motor Resistor Test
link> Blower motor test
 

MRRSM

Lifetime VIP Supporter
Unlike the Later Model Trailblazers and Envoys... Your SUV probably has an In-Dwelling Pair of Cabin Air Filters that have gotten thoroughly clogged up and have become very restrictive to the expected Smooth Flowing, High Volume Air Stream. @MAY03LT shows where these hidden items are... and how to Swap the Old Ones Out and the New Ones IN:

 
Last edited:

Mooseman

Moderator
Unlike the Later Model Trailblazers and Envoys... Your SUV probably has an In-Dwelling Pair of Cabin Air Filters that have gotten thoroughly clogged up and have become very restrictive to the expected Smooth Flowing, High Volume Air Stream. @MAY03LT shows where these hidden items are... and how to Swap the Old Ones Out and the New Ones IN:
Unless it was modified to accept a filter, his does not have the door for a filter. 02 and possibly 03 had the door but GM never put a filter in them and then eliminated the door altogether in later years. It can be modified to add a door and use a filter.
 

MRRSM

Lifetime VIP Supporter
Cool... This Video shows How that gets done:

 
OP
OP
E

emedlin

Well-Known Member
Finally got time to test it. It is the control module that went bad. I can see the voltage go up and down on the signal and positive wires going into the module when I change the HVAC. But, the voltage going to the fan never changes or changes randomly. Now to order the part, 15-81773, and swap it out. And splice some wires as they changed / improved the connector.
 

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