Test L: Temperature Control Is Inoperative/Does Not Operate Correctly

PINPOINT TEST L: TEMPERATURE CONTROL IS INOPERATIVE/DOES NOT OPERATE CORRECTLY

Normal Operation
Under normal operation, to rotate the blend door actuator, the HVAC module supplies voltage to the blend door actuator motors through the door actuator feed A circuits, and supplies ground through the door actuator feed B circuits. To reverse the blend door actuator rotation, the HVAC module reverses the voltage and ground circuits.

The blend door actuator feedback resistors are supplied a ground from the HVAC module by the blend door actuator return circuits and a 5-volt reference voltage on the blend door actuator reference circuits. The HVAC module reads the voltage on the blend door actuator feedback circuits to determine the blend door actuator position, by the position of the actuator feedback resistor wiper arm.

Door actuator feed A circuits
- (Dual automatic temperature control/electronic automatic temperature control [DATC/EATC]) LH Blend - CH238 (YE/OG)
- (Electronic manual temperature control [EMTC]) LH Blend - CH233 (VT/BN)
- RH Blend - CH212 (BU/OG)

Door actuator feed B circuits
- (DATC/EATC) LH Blend - CH239 (BU/WH)
- (EMTC) LH Blend - CH234 (YE/GN)
- RH Blend - CH213 (BN/GN)

Door actuator return circuits
- LH Blend - RH111 (GY/BU)
- RH Blend - RH111 (GY/BU)

Door actuator reference circuits
- LH Blend - LH111 (BN/WH)
- RH Blend - LH111 (BN/WH)

Door actuator feedback circuits
- (DATC/EATC) LH Blend - VH440 (BN/BU)
- (EMTC) LH Blend - VH439 (GY/VT)
- RH Blend - VH441 (WH/BN)

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Blend door actuator motor
- HVAC module - EATC
- HVAC module - DATC
- HVAC module - EMTC
- Stuck or bound linkage or door

L1-L2:

L2-L3:

L4-L5:

L6-L8:

L8-L9:

L10-L11:

L12-L13:

L13-L14:

L14-L15:

L15-L16:

L16-L17:

L17-L18:

L18-L19: