Slow to spin up AC blower

emedlin

Original poster
Member
Jan 25, 2012
150
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

Member
Dec 16, 2018
730
Sterling Heights, Michigan
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

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Supporting Donor
Member
Oct 22, 2015
7,639
Tampa Bay Area
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:

 
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Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
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.
 
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mrrsm

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Supporting Donor
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Oct 22, 2015
7,639
Tampa Bay Area
Cool... This Video shows How that gets done:

 

emedlin

Original poster
Member
Jan 25, 2012
150
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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