2003 GMC Envoy, No A/C Vent Control, B0263

This 2003 GMC Envoy came in with the complaint that the a/c will only blow out the defrost and floor. Not through the dash vents. I checked codes and found a code B0263 for a fault with the mode actuator. I first ran into this problem after changing a battery in one of these vehicles last year. Whenever the battery is disconnected the HVAC unit will perform a recalibration of all doors. This causes the door motors to be moved full cycle and the mode door will stick some times. I now hook a jump box to the system before changing the battery in Trailblazers or Envoys to prevent a recalibration from occurring. This way I will not be blamed for a stuck actuator motor.

Anyways to change the actuator motor, first drop the hush panel under the driver’s side of the dash. There are some parts that have to be disconnected from the panel including the turn signal flasher assembly shown in the next picture.

Next, I removed the lower dash knee panel to have a little more room to work.

I had to pull a push pin retainer out at the left side of the duct work in order to remove the driver’s floor vent.

Now, I could finally see the actuator on the side of the heater a/c box.

I removed the actuator and installed the new one. Performed a recalibration with my Tech 2 and put all the panels back in place. A recalibration can be done by disconnecting the battery for at least one minute, reconnect the battery, start the engine and leave the a/c controls alone. I would recommend letting the engine run for at least two minutes, turn the ignition off for at least ten seconds but no more than thirty seconds and then restart the engine so that confirmation of the repair can be done.

I do not recommend connecting the wiring to the actuator until it is installed. They come prepositioned for easier installation.

The notch at the lower edge of the gear is an alignment point. There is a corresponding tab on the door linkage that needs to be lined up with this notch.

To purchase the mode valve actuator, please click here.  To see updated information about actuator positions and alignment, please click here.

243 discussions on “2003 GMC Envoy, No A/C Vent Control, B0263”

  1. No, it is a different actuator than the one described in the repair post. I was looking to see which one it actually is but, my data base is not real clear about it. My gut feeling is that it is one of the other actuators on the same side, but at this point I just do not know. Anybody else care to submit and answer?

  2. not sure if I have the same problem or not….2002 envoy….a/c works everywhere except drivers side. All vents on drivers side blow HOT. GM dealer referenced CODE B0414. They recommended Temp actuator. Is this the same actuator?

  3. Thanks for posting the tips and for your email follow up. I had a bad mode valve actuator on my 2006 Envoy Denali (with dual temp and power pedals)and just repaired it in under 3 hours for under $60. Dealer estimate was $579 – a fair price given standard hours but more than I could afford. Similar to your blog but different for the Denali – I removed the lower left hush panel, knee panel, and steel knee panel plate (it is blow-molded plastic in your photo). I removed the three bolts holding the adjustable gas pedal to the adjustable brake assembly and unplugged the connector, and swung the gas pedal aside. This allows access to and removal of the duct (simlar to duct in your third photo) above the power pedal. My duct was in two pieces, and I only removed part above the pedal. This allowed access to the actuators. I was then able to remove the bad actuator – held in by two 5.5 MM screws. I put the new actuator in place loosely, and was able to reach above the actuator to align the flapper key with the actuator cam notch, then I installed and tightened the two screws. The right half of the duct work would not snap back in place on both ends, so I had to remove the push pin on the far left side of the remaining duct half (above the driver’s left foot), and slid the duct to the left a couple inches to get clearance needed, then reassembled all and it works great.

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