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.
Thanks Sparky for the advice.I had issues with my defrost blowing cool air, even after the engine has heated to a hot temp.One morning I had to pull over to a gas station and manually wipe my front windshield. Also had issues with heat blowing on passenger side and cool air blowing on driver side. After replacing blend door actuator all issues are resolved.
Yes, the two screws are in a tight spot but don’t let that deter you. I use 7/32 socket, 2 inch extension and a small socket wrench. You will need both hands to remove screws, one to keep socket from slipping off screw and the other to turn the socket wrench. Three pillows was placed on the driver side floor for body comfort. It really wasn’t that difficult to remove. LOL if you are a large person it may be difficult for you.
If I digress a little, there are hundreds of parts on GM vehicles that’s made in Mexico or China. GM vehicles should be labeled as semi-foreign vehicles. Peace from “D”
Glad to hear you were able to clean some connections and have the actuator start working again. The vast majority of the times that I replace the actuators there is an internal gear problem as evidenced by a ticking noise.
Good info here…My problem was blend door not operating and fresh air door intermittent. I removed blend door motor and noticed the motor was rotating, so I reinstalled it and it worked for 2 days, about the same with fresh air door. I checked control module and motors. Control module check good and all the motors read about 39 ohms…While moving the connector to one of the motors I noticed it started working. With years of electronic experience, I automatically knew what the problem was. Sprayed contact cleaner on connections at motors, recalibrated, and everything has been working fine for over a month. Had I not seen conditions such as this over the years, I would have replaced the actuators which probably would have resolved the problem (bad connections). Your site was extremely helpful in getting me on the right track.
Thank You:
CH
thanks Sparky, my wife can now have heat again. Thanks for the easy to follow instructions they were very helpful. Everything works perfectly Keep up the good work. Thanks Again
If the screws were very loose the actuator could have backed off of the shaft to the point that it would not move the door. Only time will tell if that was your problem or not. I would recommend doing the recalibration though.