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98 STS Blend Doors?

6701 Views 16 Replies 6 Participants Last post by  MoistCabbage
I have had the STS about 9 months now and having gone through summer/winter season, I think I may have blend door issues.

In the winter, the heat is working, but the car is still cold.
In the summer, the air is working, but the car is still hot.

I believe from the blend doors not closing completely and letting outside air into the cabin. Gets a little better on Recirculate, but still not blocking the outside air.

Where are the blend doors on a 98 STS? No codes.

Robert D
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Sub, yes. I have been using Recirc to make it better, but still getting external air into the cabin. The reason I want to stop external air is because there is so much of it
The system (when working properly) doesn't just dump ambient air into the car at ambient temperature, it heats or cools it accordingly to provide the desired temperature. The problem isn't that "too much" ambient air is entering the car. If you're not getting any codes, first blow out the cabin air temp sensor with compressed air as submariner suggested. (personally I would use canned air as opposed to air from a compressor, only because it is completely clean and dry) also check that the sensors fan is running. With the car on, put your air up to the grille to the left of the steering wheel, you should hear a faint whirring sound.

If it isn't running, it might just have to be lubed with light machine oil. The fan/sensor is accessible by removing the cover on the drivers side of the dash (with the door open). Stick your finger through the rubber gromet and pull straight off. You'll see the fan/sensor is held on with one bolt (10 mm I think) remove it with a socket on an extension, carefully guide the sensor out of the opening in the side of the dash and unplug it. Hopefully that solves the problem and it's not an "in dash" sensor or blend door, they're a pain to get at.
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When you say the rear works great, do you mean the heat is very warm and the A/C is nice and cold? Also, in your first post you say "In the winter, the heat is working, but the car is still cold.
In the summer, the air is working, but the car is still hot.". What temperature do you set the system to in summer/winter?
It's all electric motors, no vacuum.

Go to the top of the Seville/Eldorado page, and read the "sticky" thread on how to pull codes. List any codes you may find, AND THEIR DEFINITIONS, here (there's a link within the sticky with definitions).

BTW, :welcome:
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