AC goes to heat while running

[Ozlander]

06 Yukon XL
While using the AC, from 1 minute up to several hours, the front air starts blowing hot air out the vents.
The only way to fix up is to turn engine off and restart. Works every time. This started out maybe once a month and is now almost daily.
Rear air is always cool when this is happening.

 

[wjburken]

06 Yukon XL
While using the AC, from 1 minute up to several hours, the front air starts blowing hot air out the vents.
The only way to fix up is to turn engine off and restart. Works every time. This started out maybe once a month and is now almost daily.
Rear air is always cool when this is happening.

You might have blend door going out. Pretty common.

 

[SnowBuck]

2005 XL
Has exact same problem. Mine hot on the left/cold on the right. VERY common. Don't jump to the conclusion that it is the actuator on the passenger floor even if it was making clicking sounds. Mine was the difficult one ... behind the middle dash. Replaced and works perfectly now. Even the floor actuator stopped clicking.

 

[Doubeleive]

06 Yukon XL
While using the AC, from 1 minute up to several hours, the front air starts blowing hot air out the vents.
The only way to fix up is to turn engine off and restart. Works every time. This started out maybe once a month and is now almost daily.
Rear air is always cool when this is happening.

do both sides get warm or just the drivers side?

 

[Ozlander]

Both sides, if I turn the temp control up to 90, blower slows down and maybe stops. Thus it thinks it still in the cool mode.
If I turn the temp control down to say 60, Air goes from vents to floor outlet, still hot air.
Turns system off and back on does nothing, still blows hot air. Rear system still blowing cool air all thru these changes.
Only way to fix it is to shut ignition switch off, then restart engine. Set to neutral, off, on, start, back to Drive. Less than 10 sec.
O

 

[ivin74]

2005 XL
Has exact same problem. Mine hot on the left/cold on the right. VERY common. Don't jump to the conclusion that it is the actuator on the passenger floor even if it was making clicking sounds. Mine was the difficult one ... behind the middle dash. Replaced and works perfectly now. Even the floor actuator stopped clicking.

Mine is doing the same, do you have a part number? How many actuators do the NBS have?

 

[Doubeleive]

Both sides, if I turn the temp control up to 90, blower slows down and maybe stops. Thus it thinks it still in the cool mode.
If I turn the temp control down to say 60, Air goes from vents to floor outlet, still hot air.
Turns system off and back on does nothing, still blows hot air. Rear system still blowing cool air all thru these changes.
Only way to fix it is to shut ignition switch off, then restart engine. Set to neutral, off, on, start, back to Drive. Less than 10 sec.
O

in that case I would suspect the controller being bad, especially if it is the digital one

 

[SnowBuck]

Mine is doing the same, do you have a part number? How many actuators do the NBS have?

Someone answered one of my posts:
"There are 4 actuators for the front AC and 2 in the back. The left one is on the bottom behind the console or middle area. The right side is on top in the middle. The recirc is on top but towards the right and the "blend" is under the driver's foot well.

The ambient sensors in the 900s look like little speaker grills in the headliner, 1-3 depending on trim level and options."

And RockAuto has the controller for about $140.

 

[Ozlander]

in that case I would suspect the controller being bad, especially if it is the digital one

The controller being the one in the dash were you set temps, off and on etc?

 

[Doubeleive]

The controller being the one in the dash were you set temps, off and on etc?

yes the main controller