Have a 2007 Tahoe with automatic climate controls. The front air works great for about 1 to 2 hours before air stops blowing out of any of the vents. We I turn the fan to high the blower is running at a high speed but still little to no air from the vents. The rear air works just fine without any problems. Can turn the A/C off for about 20 to 45 minutes and once I turn the A/C back on, it will work for another 1 hour or so before I have to repeat the process on long road trips.

I have already replaced the blower moter, blower resistor and cycling switch.

Any ideas on what's next?

 

so the motor is spinning, but air isn't coming from the vents?

you've tried adjusting it to face/feet just for testing?

are you saying it stops blowing cold or it stops blowing any air what so ever?

 

Not sure why you replaced the blower motor if it was still blowing air. If the rear A/C is working, then it can't be the cycling switch and all the resistor does is provide a voltage drop for the different speeds.

Plus same questions as STS above.

 

@SabrToothSqrl

You are correct, the blower still blows at the different speed rates based on the HVAC control settings but there is NO air flow from any of the vents in the front cab area of the truck. (dash vents, floor vents and defrost). Have tried all vents settings.

 

that's freaking weird lol.

did the device that controls the face/feet flow fall/break/disconnect?

I don't even know what to take apart to get at that, but my guess is something is blocking the air flow...

 

Nothing seems disconnected. Tonight, I will pull everything apart and check for any blockage. It is very weird. Like I stated earlier I can turn the A/C off for about 30 minutes and it will start back working without any problems for about another hour.

 

Check the blower wheel to make sure that it is not loose on the motor shaft.

With the blower on high, stand outside on the passenger side near the intake at the base of the windshield and listen for any airflow.

Edit: Since it seems to work and then quits makes it sounds like something other than a blockage.

 

Sounds like the a/c is icing up. Usually caused by reduced airflow over the evaporator.

 

Good thought. That can be caused by low refrigerant.

 

if you take this apart, post some photos for us.

I'd like to see what it looks like.

thanks.