This 2004 Chevrolet Impala came in with the complaint that there was no heat on the driver’s side of the car. It could very well have been the reverse, no a/c on the driver side as the problem turned out to be a faulty driver’s side blend air door actuator assembly. There was a code B0408 stored for the that actuator. If you do not have a way of checking for codes, the actuator should be watched to see if it responds to command inputs. When there is a no or poor heat condition the coolant level should always be checked first.
To access the actuator the lower dash cover has to be removed but first the cover on the left end of the dash has to come off.
Then the driver’s side hush panel.
There may be a couple of screws along the lower edge of the panel. After they are removed the cover will pull off the dash and the trunk release switch can be disconnected if present.
Four 10 mm headed screws are recessed behind the metal knee bolster and there are several 7 mm headed screws around the exterior of the panel.
You can now see the actuator in the center of the following picture. The white label is easily visible. Testing is difficult at best but here is what needs to be done if you do not have a scan tool that will interface with the system. Back probe the yellow wire and the dark blue/white wires with a voltmeter. There should be 0 volts for a stationary command. There should be a 12 volt positive for a commanded movement and a negative 12 volt reading in the opposite direction. Note that the code may have to be cleared before the control head will make the commands. Use a scan tool, disconnect the battery or remove the DIC/RKE fuse for at least 60 seconds.
This is what the actuator looks like out of the vehicle. The screws holding the actuator to the case should have 5.5 mm heads. To order this actuator please click here.
After replacement of any of the actuators a recalibration procedure needs to be performed. It is very simple though. Turn the ignition off, remove the DIC/RKE fuse from the right / passenger side, interior fuse box. It is a 10 amp fuse. Leave the fuse out for at least 60 second. Install the fuse and turn on the ignition. Do not touch the a/c controls for at least 60 seconds. switch the key off for at least 10 seconds and the recalibration will be complete when you restart the engine.
Moving the door by hand can be a bit difficult and is normal. The main thing is, it should be smooth across the range of travel. Even though the actuator is small, it has a good amount of torque because of the gear reduction drive. There have been cases where just unplugging and reconnecting the harness has corrected the issue. Although my thinking is that if it is acting up, just replace it. Too many times of disconnecting and reconnecting the harness and the harness terminals will be worn out. Also it won’t be long and a gear will break anyways. Do it once and drive it for another 5 – 10 years without having to worry about it.
Hey Sparky, thanks for the info, it came in real handy on my 2005 Impala, no heat/driver side problem. When I got the actuator off I turned on the ignition to see if it would function. It did indeed start rotating and would reverse direction when I moved the temp lever. I then reached in to rotate the door shaft, it was pretty stiff, but I got the door to move and when I ran the car I had heat on the driver’s side again. My question is how freely should the door shaft be to turn and can the actuator still function and not have enough power to move the door?
Dude, just wanted to let you know how much I appreciate you putting information out there like this. I fixed my heat today with your help and just wanted to say you’re the man
Thanks Sparky. everything came apart and the recalibration process worked just as you have explained it in the original post.
If it has single zone temperature control it would be more likely than if it has dual zone. Don’t forget the simplest thing is being low on coolant.