Review on Air Blend Door Actuator Replacement for Chevrolet/GMC, OE: 89018365, 604-106, 52402588 - Compatible with 1994-2012 Silverado 1500 & 2500, Tahoe, Sierra - HVAC Heater Blend Control Motor by Noel Pilla

The item is perfect. The lousy GM design makes it difficult to pull out the old one. To remove the protection you will need a 7mm deep socket. You will then need a 1/4" drive and a 7/32" socket to remove it. Due to the poor construction, one of the three screws (on the driver's side) of the guard and the left screw of the door check are difficult to reach. This part is the plug and play part. While you are there you can also replace the 2 cabin filters.