2004 Chevy Tahoe HVAC question...

[A930Rocket]

Not much information to go on as I just picked up the car tonight from my brother, but I know the power of PPOT.

It's a 2004 Chevy Tahoe 2WD with a 5.3 and 104K on the clock.

It has dual temp controls and rear HVAC. With the emgine and AC on, it blows hot air out the drivers two vents and cold air out the passenger side vents. The rear blows cold.

Are there any common problems that would cause this? Could it be a bad dash temperature control unit? A bad flapper in the dash?

Any other information needed to go on?

With a new battery, tires and a detail, it's going to be a great 4th car for us.

[stomachmonkey]

Most likely a flapper.

They can get out of sync if you start them up with the HVAC running.

Best practice is start car with HVAC Off, wait a second or two then turn on.

That said the motors also burn out.

You can hear the flappers move, get everything going and switch between floor and dash vents.

Listen for flapper moving.

If it's the center dash vent you can pull the panel above the tranny tunnel and see it actuate.

104k on the clock is nothing for that motor.

FWIW, don't let the family slam the doors, my most common maintenance item on both my Tahoe and Yukon are window actuators. The plastic take up reels break. Cheap and easy to replace though, just annoying.

[pen15]

You have a bad drivers side temp door actuator. Very common problem. There is one for each side. One is located on the bottom of the hvac box near the center bottom of dash. The other is on top of the box near the center of dash just visible thru glove box opening with glovebox removed. You will have to check and see which one moves when pass side temp is adjusted and the other will be your culprit. Only buy the new actuator from a dealer with the last 8 digits of your vin. Nearly impossible to get the correct one from an auto parts store. Do not plug in new part until it is installed either. If it is the one on top of the hvac box it calls for something like 7 hours to replace by way of removing dash. I have done dozens of them in less than 30 minutes thru glove box opening. Not easy but doable.

[pavegeno]

Funny...I've been chasing a rear that a/c won't work on my 2002 Yukon. Additional problem is that no one here in Stuttgart is used to working on GMCs so they are clueless. Fortunately, the front a/c does the job here as it doesn't get too hot. They share the same freon lines, so I'm convinced there is something electrical not turning on the rear evaporator. Uggggh!

[pen15]

Originally Posted by pavegeno

Funny...I've been chasing a rear that a/c won't work on my 2002 Yukon. Additional problem is that no one here in Stuttgart is used to working on GMCs so they are clueless. Fortunately, the front a/c does the job here as it doesn't get too hot. They share the same freon lines, so I'm convinced there is something electrical not turning on the rear evaporator. Uggggh!

Both evaporators work at the same time. If one is cold the other is too. There is a air door that directs heat to either the heater core or evaporator. It's not uncommon for the rear ac lines to leak and get blocked off or removed due to the cost to replace them

[pavegeno]

The rear one doesn't work...no pool of water dripping from the back like it always did. Warm air out of the vents.

[A930Rocket]

After doing some reading online, it might be an actuator. I'm reading the driver side HVAC actuator is either on the passenger side above the transmission tunnel or the gas pedal. Maybe the year determines this?

[mattdavis11]

Happens all the time when a battery dies or is replaced on those vehicles. You need to pull the hvac fuse, 10amp, under the hood, with the ignition turned on. Then turn off the ignition, replace the fuse, turn ignition on, do not start, let sit for two minutes, you should hear the actuators cycling, turn ignition off, then on. Should return to normal operation. Repeat as necessary. Also changing the temperature setting on both sides to full hot, or full cold during the process can help too.

[A930Rocket]

Thanks guys. I'll give your ideas a try!

[boosted 89]

pen 15 nailed it....Door actuators are very common on the Chevrolets. Drivers side actuators are easy to replace. Just remove the passenger side lower insulator panel under passenger side glove box area..usually 3x7mm screws..The actuator is on the bottom of the heater box.. 3x 5.5mm screws hold it on.located just to the right of the centre of the heater box. I replace these on the daily at the dealership I work at.

Chris

[A930Rocket]

Chris

What would the dealer charge to swap it?