For 1990-2009 cars

### Removal Procedure

Important: Production modules are built with a non-adjustable mode valve to the heater door linkage. If adjustment is needed, install the service linkage as follows.

1. Reach under the dash and remove the threaded end of the linkage rod from the upper linkage adjuster by gently pulling the linkage rod straight outward.
2. Remove the linkage rod from the lower retainer by positioning the rod on the open side of the retainer clip and gently pulling straight outward.
3. Remove the upper linkage adjuster from the mode valve assembly by pinching the adjuster closed and pulling straight out.
4. Remove the lower linkage retainer from the mode valve assembly by pinching the back of the retainer and pulling straight out.
5. Remove the linkage spring by grasping the rear of the spring with pliers and pulling back and up out of the rear spring retainer.
6. Unhook the spring from the front spring retainer.

### Installation and Adjustment Procedure

1. Hook the spring into the front spring retainer.
2. Grasp the rear of the spring with pliers and pull back to hook the spring into the rear spring retainer.
3. Install the upper linkage adjuster and the lower linkage retainer by pressing into place on the mode valve and the heater valve assembly.
4. Install the linkage rod into the lower linkage retainer and snap into position.
5. Position the mode valve and the heater door levers in the full forward position.
6. Snap the threaded end of the linkage rod into the upper linkage adjuster.