AC only blows out defrost vent

[JoeTahoe]

How can I post this message for help?
I can't figure out how to make a post?
I have a 2001 Z71 4WD Tahoe

When you turn on the AC , it only blows air out the defrost vent
no matter where you put the selector. Fan motor works fine, Tem switch works fine, but the other is stuck blowing out in defrost no mater which vent you turn to.
I am trying to determine if it is the HVAC control module or the MODE actuator? before i buy any parts.
Dealer wants 110.00 to Diag truck. Wants 1.5 hr labor to fix it, and
the module is 324.00 at the Chevrolet dealer.
I have searched the internet for steps to diagnose the problem, but can not find any. Salvage yard wants 70.00 for the control but no guarantee. You connect it and it dosn't work it is still yours. No
refund. I am 70 years old without a job and SS wont pay for the repair.
Any help would BE APPRECIATED.
Joe

 

[HiHoeSilver]

How can I post this message for help?
I can't figure out how to make a post?
I have a 2001 Z71 4WD Tahoe

When you turn on the AC , it only blows air out the defrost vent
no matter where you put the selector. Fan motor works fine, Tem switch works fine, but the other is stuck blowing out in defrost no mater which vent you turn to.
I am trying to determine if it is the HVAC control module or the MODE actuator? before i buy any parts.
Dealer wants 110.00 to Diag truck. Wants 1.5 hr labor to fix it, and
the module is 324.00 at the Chevrolet dealer.
I have searched the internet for steps to diagnose the problem, but can not find any. Salvage yard wants 70.00 for the control but no guarantee. You connect it and it dosn't work it is still yours. No
refund. I am 70 years old without a job and SS wont pay for the repair.
Any help would BE APPRECIATED.
Joe

Mode door actuator for where it's blowing. Blend door actuator for hot/cold.
These are more likely culprits than the control module in the front. The rear control module being bad is more common.

 

[S33k3r]

How can I post this message for help?
I can't figure out how to make a post?
I have a 2001 Z71 4WD Tahoe

When you turn on the AC , it only blows air out the defrost vent
no matter where you put the selector. Fan motor works fine, Tem switch works fine, but the other is stuck blowing out in defrost no mater which vent you turn to.
I am trying to determine if it is the HVAC control module or the MODE actuator? before i buy any parts.
Dealer wants 110.00 to Diag truck. Wants 1.5 hr labor to fix it, and
the module is 324.00 at the Chevrolet dealer.
I have searched the internet for steps to diagnose the problem, but can not find any. Salvage yard wants 70.00 for the control but no guarantee. You connect it and it dosn't work it is still yours. No
refund. I am 70 years old without a job and SS wont pay for the repair.
Any help would BE APPRECIATED.
Joe

Normally the diagnostic fee is credited toward the repair charges if the mechanic performs the repairs. I know it's not much to save, but if you have to have them do it, that might save you the diagnostic fee.

Also, it might help if you gave us an idea of where you are located. I have a really good mechanic; for folks who don't do there own work... Well, they may know folks as well.

Good luck!

 

[M1Gunner]

You can unplug the actuator and ohm it out see if the motor is shot or shorted. You can also check voltage on the harness side and watch the value as you change position with the switch.

 

[OneofFew]

The mode door actuator is above a duct, right above the accelerator pedal. You may be able to manually help it get unstuck and lube the part it moves. Once you see it, turn the mode selector knob and watch the actuator move and get stuck, help it past that spot, lube and it may stay working for a while. chances are, it is just tired.

 

[ScottyBoy]

I'm now having this SAME exact issue on my 2001 Suburban. My air is stuck blowing out the defrost vents, no matter what setting I put it on. I can hear a very faint clicking in the dash if I turn the mode knob to change the settings. I'm thinking the mode actuator is bad, or has stripped out gears or something. Does anyone know the part number for the mode door actuator? Searching online, I can only find the blend door actuator.

 

[Doubeleive]

I'm now having this SAME exact issue on my 2001 Suburban. My air is stuck blowing out the defrost vents, no matter what setting I put it on. I can hear a very faint clicking in the dash if I turn the mode knob to change the settings. I'm thinking the mode actuator is bad, or has stripped out gears or something. Does anyone know the part number for the mode door actuator? Searching online, I can only find the blend door actuator.

what year & model, engine size?

 

[ScottyBoy]

what year & model, engine size?

As I stated in my previous post, I have a 2001 Suburban. And I have the 5.3 liter LM7 engine, non flex fuel.

 

[Doubeleive]

it's hard to say for sure which one it needs but there is couple different ones, pull it out and visually match it to one of these.
https://www.rockauto.com/en/catalog...conditioning,heater+blend+door+actuator,10721