1998 blend door actuator on a 1998 Buick Lesabre

Check out the videos and also click on the images tab for diagrams.

https://www.google.com/search?q=04+buick+LeSabre+blend+door+actuator+locations

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There is not much unique about the blend door setup in your GM vehicle. I have found YouTube to be very useful in seeing the location of the components - try https://www.youtube.com/watch?v=8AYILDQvJZk as an example.

Did you replace them ? If not working correctly you probably need to replace it. Do you hear a clicking noise behind the dash ? Does your buick have manual or automatic climate control ? You say blend door actuator ? right or left ? Or mode door ? Mode door would be for moving from floor to vent to defrost . Blend door actuator is Temperature Valve Actuator right or left side.
After replacing one , their is a Actuator Recalibration that must be done . One using a professional scan tool or one that doesn't need a scan tool

Calibration Procedure without a Scan Tool
Turn OFF the ignition.
Remove the battery positive voltage circuit fuse of the Instrument Panel Control Module.
Important: The module memory will not clear if the battery positive voltage circuit fuse is installed in less than 60 seconds.
Wait 60 seconds.
Install the fuse.
You probably don't know where the I/P control module fuse is ?
Fuse is located under the rear seat , left side . Fuse # 37 10amp . HVAC (BATT) .

it is controlled by an electronic actuator. look up blend door actuator on google with your year make and modle and it will show a diagram and location, also a part number if you would like to replace.

Same problem on my 98 Regal GS; remove glove box, locate the blend door actuator, (black odd shaped box with metal "ring"). Remove the box and manually turn the blend door shaft it was attached to. If you get cold air, it's the actuator you removed. About 30-40 dollars.

Blend door not working, first of all check if it is vacume actuated or power, go to any parts shop and get your self a print out and go from there.

NOT WORKING MEANS. NO AIR FLOW? OR TEMPERATURE? SOUNDS LIKE A BLEND DOOR ISSUE. IF YOU MOVE THE MODE CONTROL ON THE DASH TO A DIFFERENT POSITION DOES ANYTHING CHANGE. IF YOU HEAR A CLICKING OR POPPING NOISE THE PLASTIC ARM ON THE BLEND DOOR ACTUATOR IS BROKEN.

There is a blend door actuator motor that is not working,the dash has to be removed back toward the seats to access the actuator motor.

this is caused by a fault in the dual climate zone air temperature control blend door or the actuator that operates it.

There is a blend air actuator on the passenger side that causes the blend air door to stay open to heat no matter what. It's below the left side of glove box, facing dash, and you can work it by hand and get it to close. If that works, get a new one. They're very easy to install.