Chart 8 Improper Temperature Regulation

TEST DESCRIPTION:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks to see if improper temperature regulation is due to air mix valve movement.
2. Checks to see if improper temperature regulation is due to poor aspirator air flow.
Procedures for Checking Aspirator Air Flow:
A) Engine running, vehicle not in direct sunlight.
B) Select "HI" blower speed and any mode except "DEF."
C) Hold paper strip at one end with the opposite end over in-car temperature inlet.
D) Lower paper strip until it is about 1/2" above in-car temperature inlet.
E) If aspirator air flow is good, the end of the paper strip will be sucked down over inlet.
3. Checks accuracy of in-car temperature sensor.
4. Air Mix Valve Adjustment
A) Lift straight up on air mix valve link to release it from programmer arm.
B) Key "ON," select MAX HEAT and wait for programmer arm to stop moving.
C) Manually pull air mix valve link toward passenger door until it hits mechanical stop (mix valve in MAX HEAT position).
D) With both the air mix valve link and programmer arm in MAX HEAT position, snap air mix valve link back into programmer arm.
E) Visually check movement by selecting different temperature settings.
5. Checks to see if binding or stopping is due to valve or DC motor.