Air vents not changing

LORNE GARCIA

MEMBER
2002 CHEVROLET TAHOE
5.3L
V8
2WD
AUTOMATIC
140,000 MILES

When my air is turned on I have no air or very faint air coming from my vents. When I turn the defrost on or the heater I have no air coming from either places. The blower is working fine but it does make a loud bellowing sound when turned on high. It almost sounds as there is something plugging the ventilation up. I have my dash completely opened up. I watched my mode actuator as I went through all the modes on the unit and moved but very little. I watched my temperature actuator and it also moved very little, not only that but it kept moving back and forth. I pulled my temperature actuator and then moved it manually and I got my heat coming from the floorboard. Once I moved the flap door by hand I could not move it again unless I turned off my air. I have not gotten to my blend door yet but I figure I better contact someone who knows more on this subject before I pull that out. So basically if I turn the unit on I am not getting air where I am supposed to in any mode. The blower is working. I can hear movement in my dash. And the only time I have gotten air out where it supposed to be is the lower heater when I turned the air temperature actuator. Can you help?

8 Replies

JIS001

MECHANIC
3,411 POSTS

It sounds like you have a restriction. Since you have the dash out it should be easy to remove the cabin air filter. Your filter is either very dirty or something got sucked in. Attached images. #26 is the cabin filter location. Pull filter and upload picture to see what is going on.

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Tuesday, February 13th, 2018 AT 10:13 PM

SHONDA76

MEMBER
1 POST
2002 CHEVROLET TAHOE
4 CYL
4WD
AUTOMATIC
190,000 MILES

Vents in the back is not blowing out no air.

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Thursday, December 3rd, 2020 AT 9:40 AM (Merged)

2CARPRO JACK

MECHANIC
11,533 POSTS

There is a blower motor in the rear of the vehilce on the side (look under for the hoses telling which side it is on)You will have to remove theside interior panel to gain accss to theblower motor. Once there use atest light to verify power/ground at the motor when it is switched on. Ifit has power/ground the motor is bad, if not there should be a fan speed resistor next to the motor(power wires for motor will go to it) test for power into that.

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Thursday, December 3rd, 2020 AT 9:40 AM (Merged)

ERIN KEITHLEY

MEMBER
3 POSTS
2002 CHEVROLET TAHOE
5.3L
V8
4WD
AUTOMATIC
257,000 MILES

All of a sudden one day I turned on the A/C and I had no air mowing out of my vents in the front. Air will blow out when it’s directed to the floor or defrost, but not the “front” vents. I can hear the compressor kick on and the fan blow. Blow motor resistor was changed about about two years ago, but not the blower motor. At the same time, I have no air at all coming from the rear. I replaced the blower motor in the rear not quite a year ago, but I hear nothing when I turn the fan on in the rear.

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Thursday, December 3rd, 2020 AT 9:40 AM (Merged)

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

There is a mode door in the system that is commands vent operation. I attached the procedure for removal with some pictures.

As far as the blower, make sure there is power to the blower resistor at the rear. Good chance the resistor is the issue.

Roy

REMOVAL PROCEDURE

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1. Remove the floor air outlet duct extension (1) from the floor duct (2).

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2. Disconnect the electrical connection at the mode actuator (10).

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3. Remove the mode actuator mounting screws from the HVAC module.
4. Remove the mode actuator as an assembly with the actuator cam.

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Thursday, December 3rd, 2020 AT 9:40 AM (Merged)

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

Okay, the problem with your vents is probably going to be with your mode door actuator. In the diagrams down below I have included the factory directions for the removal and installation of the mode door actuator for your vehicle. I have also included a wiring diagram for your rear blower motor as well as a guide for how to inspect ground connections. The problem for the rear blower motor could be a bad ground connection at ground #408 which is located on the right D pillar of your vehicle. Please go through these guides and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros

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Thursday, December 3rd, 2020 AT 9:40 AM (Merged)

BAYRIDGEBKLYN

MEMBER
1 POST
1999 CHEVROLET TAHOE
V8
4WD
AUTOMATIC
104,000 MILES

I have had some work done on the vehicle, replaced the compressor and other minor parts (do not remember what they were) but I do not think the air coming into the vehicle is cold enough. Mechanic disagrees.
I just drove 90 one way and had the air on max and the fan at it's highest setting. I never had to shut the unit off in all that time.
I have owned Tahoes for over 13 years and at these settings eventually it got too cold.

I also have a 1990 Ford F-150 pick up truck with a new compressor but at max. Setting It gets too cold within 10 minutes at the longest.

I realize that the truck has a smaller cooling area than the Tahoe but the air coming out of the truck is ice cold.

What should the temperature be?

Bob Slone

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Thursday, December 3rd, 2020 AT 9:40 AM (Merged)

JACOBANDNICKOLAS

MECHANIC
109,700 POSTS

Bob,

The temp varies on different vehicles. I would say if you can get it into the 50's you're doing well. Keep in mind, if you keep it on MAX AC, you are recirculating the air in the truck which can cause the AC to not work as well or actually freeze up. Use max for awhile then go to regular AC. See if that changes anything.

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Thursday, December 3rd, 2020 AT 9:40 AM (Merged)