Dash Vents Won't Blow Hot or Cold
My car is a 2003 Envoy with around 140K miles
You have probably read a lot of other posts by the time you get to this one, so I wonít go into a lot of detail thatís already been hashed over. My A/C wouldnít blow through the dash vents, no matter where the mode selector switch was set. (The mode switch is the one that selects which vents heat and air blow out of.) The vents are controlled by actuators which are just small motors that open and close various doors that determine where the air goes. Like many of the posts, my problem occurred when I reconnected the battery after storing the car for 6 months.
From all the previous posts, I figured the mode door actuator had failed. You can try the recalibration process included at the end of this blog and it might correct the issue. I tried it numerous times but although the actuator moved, it would only go one direction and then stay there. An optional double check would be to take the car to a GMC dealer and have them run a diagnostic check. My diagnosis showed code ďB0263, mode door actuator stuckĒ. The cost was $65 but I knew for sure I had the correct diagnosis. Quote for the dealer to make the repairs, $528.
I pulled the two dash panels on the driverís side under the steering column, the silver crash bracket under the column, and the plastic vent that routes air over to the driverís side. Tip: Be careful when removing the plastic vent push screw because the bracket is fragile and easily broken. You need a 5.5mm, 7mm, and 10mm sockets to remove this stuff. Looking up under the dash above the gas pedal, you will see two black actuators. The mode door actuator is the one farthest from the firewall. Ordered the actuator from Amazon, AC/Delco Part #15-73596, GM part #89018675, for $43. Removed the failed actuator with a 5.5mm socketÖ..two screws hold it in. A little tricky getting at the back screw. If you want to test the system to make sure air comes out of the dash vents, reach up and turn the actuator gear fully CW. When you are ready to install the new actuator, turn the gear on the door(not on the actuator) by hand to about the mid-point in itís travel. The white actuator arm has a notch that mates with the door gear so there is only one way it will fit. You may have to do a little back and forth to get the notch and gear to align. Then hold the actuator in place while you get the screws started and tightened down.
Now for the big test. Lots of previous posts on making sure everything is calibrated. This calibration procedure worked for me: Ignition off, A/C off, blower switch off, remove fuse 36(or disconnect the battery), wait 2 mins, insert fuse 36(or reconnect battery), ignition two clicks to run but donít start, wait 2 mins, start car, turn on A/C & blower, test mode switch. Everything should work now.