GMC HVAC actuator

Geo-TH,In · Apr 27, 2021

I took actuator apart. Determined what
position I need for cold air and put
actuator back together. Connected power
to it and it retired to full heat.
Took it apart again, put it in full cool
position. Put it back together and
ordered one from Amazon fo $16.

Auto Zone wanted another $30.
Good thing about Amazon prime, free
shipping and free return if goes through
Amazon not shipped from seller.
Should have part in a few days.
I'm hoping there isn't something wrong
with it temp control.
George

MarkB_MI · Apr 27, 2021

I think those actuators have a potentiometer to provide position feedback. A bad pot can make it drive to the opposite position it's supposed to.

Janicholson · Apr 27, 2021

All companies have problems with small motor driven gizmoes. They should all have one of three motors that are servo design and simple three wire brushless action. Putting electronice into the gearbox with lube and plastic gears is a travesty. Jim

Geo-TH,In · Apr 27, 2021

Yes it does, it's under the large black device that connects to the damper arm.
Only guessing, the manual temp lever on the dash may have a similar pot.
I hope I don't have to find out.
geo

wore out · Apr 27, 2021

/quote]

George, when the blend door actuator is tinkered with or replaced with a new one the actuator needs to be calibrated to the 'puter.

That can be done with a bi-directional scan tool or by the following procedure:

"Disconnect the battery for a few minutes. Reconnect it.

Or remove the HVAC/ECAS fuse for a minimum of 10 seconds.

Re-install the HVAC/ECAS fuse.

Then turn the key to the on position, but
don't start. Don't touch the HVAC controls. Let them do whatever they want to do. Air flow may change outlet points during this time.

Wait about 1 minute. Turn key off. Opening and closing the door can make a difference as the vehicle controls see this as "cycle" completion.

Next start the vehicle and drive it a short distance and see
how it performs."

Mite try that procedure and see if it will make your existing actuator do what it's supposed to.

Geo-TH,In · Apr 27, 2021

What position will the new actuator be in? I'm guessing in the center position.
Right now I manually set actuator to full cool, installed it and didn't connect power.
It's working OK. passenger's side slightly cooler, not much.
New actuator will arrive Friday if I'm lucky.
Where is the HVAC fuse located, under hood or next to driver's side door?
Thanks, I'll post back when mission is accomplished.
geo

Geo-TH,In · Apr 27, 2021

I read there's no calibration for manual
controls.

Digital controls need calibrated.
George

danofarming · Apr 28, 2021

Kubota wants $400.00 for the one I need.

4play · Apr 28, 2021

(quoted from post at 10:54:48 04/27/21) I think those actuators have a potentiometer to provide position feedback. A bad pot can make it drive to the opposite position it's supposed to.

Some do and this one does have a pot sensor . In the pic above the black gear on top has copper contacts at the 3 o-clock position, these sweep the circuit board pictured right below the gear.

Most new actuators are positioned in a neutral position or somewhere in mid travel. Usually you can start the spline into the blend door first then rotate the actuator to line up the mounting holes. These trucks self calibrate, no need for a scanner or specific procedure.

GMC HVAC actuator

Geo-TH,In

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MarkB_MI

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Janicholson

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Geo-TH,In

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wore out

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Geo-TH,In

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Geo-TH,In

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danofarming

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4play

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