2004 Chevrolet Impala, No Heat Driver’s Side, Code B0408

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.

76 discussions on “2004 Chevrolet Impala, No Heat Driver’s Side, Code B0408”

  1. You are the bomb!! Single mom and mine went out on me and I wasn’t willing to pay a million legs to get it fix!! It was hard to get to the 5.5mm screw, but after several attempts I got it!!! Thanks Sparky!!!

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