This 2004 Chevrolet Tahoe came in with the complaint that the air on the driver’s side would change from cold to hot while driving down the road. When it shifted to hot the customer could not get it to turn back cold. Sounds like a faulty air mix actuator to me. I checked codes and sure enough there was a code B0408 for the left air temperature actuator. I checked the commanded position versus the actual position and there was a large difference in the counts. This is only important if you have a scan tool that will access this system. There are other tricks that can be used to test that I will show later. The driver’s or left air mix actuator is located on the lower passenger side of the dash. If present the hush panel has to be removed. This one is easy because there is no floor mounted center console. If you have a floor console please see the information at this link to see how to deal with one screw.
I removed the four 7 mm headed screws and pulled the panel out of the way.
I knew I was changing the actuator, so I disconnected the wiring harness connector and removed the two 5.5 mm headed screws
Then the actuator simply pulls down. There may be some resistance if the actuator is at the full stop position.
Slide the new actuator into position, install the mounting screws and reconnect the wires. After this was done I recalibrated the actuator with my Tech 2 scan tool. If you do not have a scan tool you may disconnect the battery for one minute. Reconnect the battery and start the engine. The key point is DO NOT TOUCH the a/c controls for at least one full minute. Actually, I prefer to wait 4 minutes because I remember reading that a few years ago and the extra time does not hurt anything. After one full minute turn the ignition off. Restart the engine and check the door operation.
Proper operation can be seen in the data stream in that the commanded and actual positions are at nearly identical counts.
To do testing with a voltmeter at the harness connector you will need to test the following. Check for ignition power on the brown wire. If power is not present check the HVAC 1 fuse in the left interior fuse box. Check for a 5 volt reference signal on the light blue/black wire. All of the next tests must be done with the harness connector plugged into the actuator. The yellow wire is a low reference wire from the control head (ground, internal system not chassis). The light blue wire is the position signal wire from the actuator to the control head. If the actuator will move the voltage will change up or down depending on the movement of the actuator (between 0 and 5 volts). The dark blue wire will have basically three different voltages that are important. 5 volts is a signal to increase the door position, 0 volts is a signal to decrease the door position and 2.5 volts is a signal to hold the door position. So with that information turn the ignition on and touch the black lead of your voltmeter to the yellow wire. Touch the red lead of your meter to the brown wire and check for a reading of battery voltage. Next touch the red lead to the dark blue wire and check for either 0, 2.5 or 5 volts depending on command. You will probably need an assistant to adjust the temperature control for the driver’s side.
Something else you need to know. If you buy a new actuator make sure the part numbers match. At the time of this writing the aftermarket (non dealer) application books are incorrect. You have to buy an actuator for the passenger side to get the correct actuator for the driver’s side. Crazy but true. I cannot think of the number of actuators I have changed that have already been replaced by others. If you install the wrong actuator, it will rotate to a full stop and never move again.
This is the box that the actuator I installed came in and the numbers on the actual parts matched (52402588). The short number is 15-72971. Long number 89018365 and it is listed as the passenger or top air mix actuator. To order this part please click here.
Hello sparky I have a 2002 Chevy tahoe my rear ac only works half the time when it does not work I can hear a clicking coming from the back and another thing I noticed is when I hit a big bump in the road my ac starts to blow hot please help thank you for your time
On many vehicles the blower resistor issue was taken care of under an extended warranty program. Ten years or 150,000 miles. It was determined that it could be a safety hazard and GM sent out letters last year. The actuators are not a safety issue so no extension on those. One thing you may want to try before replacing the actuator is to disconnect and reconnect the harness connectors several times, at the passenger end of the dash. Many times light corrosion or fretting will occur and cause the actuators to act up as well.
I have been having this issue now for three years. Dealer actually fixed the problem after charging me $1700.00 for parts and labor (including parts that were not needed). The A/C worked for 1 week past the year warranty…then back to the hot drivers side, and cold passenger side. Glad to know it is the actuary and my husband can replace it. We also had the issue of control only working on setting 4 or 5 and my husband replaced the resistor. When he took it out it was “melted” I am shocked that we had not had a fire in this vehicle.
With this said, my now Chevrolet should recall and/or replace these parts since it is an ongoing and very global problem with their A/C system.
Any news about this issue I am not aware has been released?
What is the part no. we need for a 2003 Tahoe actuator?
THANKS SPARKY!!!
Did they list what parts were replaced?
Sparky – great site. Which I would have found it sooner. I had problmes wtih driver’s side hot air on my ’04 yukon (digital controls) and had the dealer fix it – $900 since it was “5-1/2” hours of labor. But, it is doing it again a week and a half later. I plan to take it back, but any adivce on what I should watch for? I feel like I’m getting screwed… but I want to make them fix their mistake since I paid for it.