Pinpoint Test U: The Auxiliary Temperature Control Is Inoperative/Does Not Operate Correctly Using The Front/Rear Auxiliary Cli
Climate Control System
Pinpoint Tests
Pinpoint Test U: The Auxiliary Temperature Control is Inoperative/Does Not Operate Correctly Using the Front/Rear Auxiliary Climate Controls
Refer to Wiring Diagram Set 52, Auxiliary Climate Control for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, to rotate the mode door actuator clockwise, the HVAC module - Dual Automatic Temperature Control (DATC) supplies voltage to the auxiliary temperature door actuator through circuit CH245 (BU/BN), and supplies ground through circuit CH244 (GY). To rotate the auxiliary temperature door actuator counterclockwise, the HVAC module - DATC reverses the voltage and ground circuits.
The auxiliary temperature door actuator feedback resistor is supplied a ground from the HVAC module - DATC through circuit RH111 (GY/BU) and a 5-volt reference voltage on circuit LH111 (BN/WH). The HVAC module - DATC reads the voltage on the auxiliary temperature door actuator feedback circuit VHA09 (VT/BN) to determine the auxiliary temperature door actuator position by the position of the actuator feedback resistor wiper arm.
- DTC B2916 Rear Blend Door Circuit Failure - The module senses an open/short in the feedback circuit or no change in actuator feedback voltage when the actuator motor has been energized.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Auxiliary temperature door actuator
- HVAC module - DATC
- Stuck or bound linkage or door
PINPOINT TEST U: THE AUXILIARY TEMPERATURE CONTROL IS INOPERATIVE/DOES NOT OPERATE CORRECTLY USING THE FRONT/REAR AUXILIARY CLIMATE CONTROLS
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U1 CHECK THE FEEDBACK POTENTIOMETER TOTAL RESISTANCE
- Disconnect: HVAC Module - DATC C228a.
- Disconnect: HVAC Module - DATC C228b.
- Disconnect: Auxiliary Climate Controls C990.
- Measure the resistance between HVAC module - DATC C228a-11, circuit LH111 (BN/WH) and HVAC module - DATC C228a-10, circuit RH111 (GY/BU).
- Is the resistance greater than 500 ohms?
Yes
GO to U2.
No
CARRY OUT the Auxiliary Temperature Door Actuator Component Test. If the actuator tests OK, REPAIR circuits LH111 (BN/WH) and RH111 (GY/BU) for a short together. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation. Auxiliary Temperature Door Actuator
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U2 CHECK POTENTIOMETER LOW- AND HIGH-SIDE RESISTANCE
- Measure the low-side resistance between HVAC module - DATC C228a-10, circuit RH111 (GY/BU), harness side and HVAC module - DATC C228b-18, circuit VHA09 (VT/BN), harness side.
- Measure the high-side resistance between HVAC module - DATC C228a-11, circuit LH111 (BN/WH), harness side and HVAC module - DATC C228b-18, circuit VHA09 (VT/BN), harness side.
- Are the resistances between 200 and 12,300 ohms?
Yes
GO to U3.
No
If the low-side resistance only is greater than 12,300 ohms, CARRY OUT the Auxiliary Temperature Door Actuator Component Test. If the actuator tests OK, REPAIR circuit RH111 (GY/BU) for an open. CLEAR the DTCs.
REPEAT the self test. TEST the system for normal operation. Auxiliary Temperature Door Actuator
If the low-side resistance only is less than 200 ohms, CARRY OUT the Auxiliary Temperature Door Actuator Component Test. If the actuator tests OK, REPAIR circuits VHA09 (VT/BN) and RH111 (GY/BU) for a short together. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation. Auxiliary Temperature Door Actuator
If the high-side resistance only is greater than 12,300 ohms, CARRY OUT the Auxiliary Temperature Door Actuator Component Test. If the actuator tests OK, REPAIR circuit LH111 (BN/WH) for an open. CLEAR the DTCs.
REPEAT the self test. TEST the system for normal operation. Auxiliary Temperature Door Actuator
If thehigh-side resistance only is less than 200 ohms, CARRY OUT the Auxiliary Temperature Door Actuator Component Test. If the actuator tests OK, REPAIR circuits VHA09 (VT/BN) and LH111 (BN/WH) for a short together. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation. Auxiliary Temperature Door Actuator
If thehigh-side and low-side resistance is greater than 12,300 ohms, CARRY OUT the Auxiliary Temperature Door Actuator Component Test. If the actuator tests OK, REPAIR circuit VHA09 (VT/BN) for an open. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation. Auxiliary Temperature Door Actuator
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U3 CHECK CIRCUIT LH111 (BN/WH) OR VHA09 (VT/BN) FOR A SHORT TO GROUND
- Measure the resistance between ground and the following:
- HVAC module - DATC C228a-11, circuit LH111 (BN/WH), harness side.
- HVAC module - DATC C228b-18, circuit VHA09 (VT/BN), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to U4.
No
REPAIR circuit(s) for a short to ground. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation.
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U4 CHECK CIRCUIT RH111 (GY/BU) OR VHA09 (VT/BN) FOR A SHORT TO POWER
- Ignition ON.
- Measure the voltage between ground and the following:
- HVAC module - DATC C228a-10, circuit RH111 (GY/BU), harness side.
- HVAC module - DATC C228b-18, circuit VHA09 (VT/BN), harness side.
- Is any voltage present?
Yes
REPAIR circuit(s) for a short to power. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation.
No
GO to U5.
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U5 CHECK DOOR ACTUATOR OPERATION
NOTE: If a jumper fuse opens while carrying out this test step, repair the circuit(s) for a short.
- Measure the resistance between HVAC module - DATC C228a-10, circuit RH111 (GY/BU), harness side and HVAC module - DATC C228b-18, circuit VHA09 (VT/BN), harness side.
- Connect a fused jumper wire between:
- HVAC module - DATC C228a-13, circuit SBP15 (WH/RD), harness side and HVAC module - DATC C228b-13, circuit CH245 (BU/BN), harness side.
- HVAC module - DATC C228a-23, circuit GD111 (BK/BU), harness side and HVAC module - DATC C228b-12, circuit CH244 (GY), harness side.
- Remove the fused jumpers.
- Connect a fused jumper wire between:
- HVAC module - DATC C228a-23, circuit GD111 (BK/BU), harness side and HVAC module - DATC C228b-13, circuit CH245 (BU/BN), harness side.
- HVAC module - DATC C228a-13, circuit SBP15 (WH/RD), harness side and HVAC module - DATC C228b-12, circuit CH244 (GY), harness side.
- Does the resistance smoothly increase and/or decrease when the jumpers are connected?
Yes
INSPECT for broken door and linkage. REPAIR as necessary. If no condition is found, GO to U7.
No
GO to U6.
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U6 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR AN OPEN
NOTE: Due to limited connector accessibility, before carrying out this test step, visually inspect the wiring between the HVAC module and actuator for opens or shorts. If no damage is visually evident, proceed with the test.
- Disconnect: Auxiliary Temperature Door Actuator C3275.
- Measure the resistance between HVAC module - DATC C228b-13, circuit CH245 (BU/BN), harness side and auxiliary temperature door actuator C3275-6, circuit CH245 (BU/BN), harness side.
- Measure the resistance between HVAC module - DATC C228b-12, circuit CH244 (GY), harness side and auxiliary temperature door actuator C3275-1, circuit CH244 (GY), harness side.
- Are the resistances less than 5 ohms?
Yes
INSPECT for binding or broken linkage. REPAIR as necessary. If no condition is found, INSTALL a new door actuator. TEST the system for normal operation.
No
REPAIR the circuit(s) for an open. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation.
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U7 CHECK MODULE CONNECTION
- Carry out the HVAC Module Cold Boot Process. HVAC Module Cold Boot Process
- Carry out the HVAC Module - Dual Automatic Temperature Control (DATC) On-Demand Self Test. Alternate Diagnostic Methods - HVAC Module - Dual Automatic Temperature Control (DATC) Only
- Operate the system.
- Does the concern return?
Yes
INSTALL a new HVAC module - DATC. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation.
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