Pinpoint Test I: Incorrect/Erratic Direction Of Airflow From Outlets
Climate Control System
Pinpoint Tests
Pinpoint Test I: Incorrect/Erratic Direction of Airflow From Outlets
Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, to rotate the mode door actuator clockwise, the HVAC module supplies voltage to the DEFROST/PANEL/FLOOR mode door actuator motor through the circuit CH228 (YE/GY), and supplies ground through circuit CH229 (WH/BU). To rotate the mode door actuator counterclockwise, the HVAC module reverses the voltage and ground circuits.
The mode door actuator feedback resistor is supplied a ground from the HVAC module through circuit RH111 (GY/BU) and a 5-volt reference voltage on circuit LH111 (BN/WH). The HVAC module reads the voltage on the mode door actuator feedback circuit VH436 (YE/VT) to determine the mode door actuator position by the position of the actuator feedback resistor wiper arm.
- DTC B1003 Mode Door Short/Failure - The module senses 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
- Mode door actuator
- HVAC module - Dual Automatic Temperature Control (DATC)
- HVAC module - Electronic Manual Temperature Control (EMTC)
- Stuck or bound linkage or door
PINPOINT TEST I: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS
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I1 CHECK THE AIRFLOW
- Ignition ON.
- Check the airflow in the PANEL, RECIRC, DEFROST and FLOOR modes.
- Is the airflow correct in each setting?
Yes
The system is operating normally.
No
GO to I2.
If the RECIRC button does not change the air inlet door position, Go To Pinpoint Test H. Pinpoint Test H: The Air Inlet Door Is Inoperative
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I2 CHECK THE FEEDBACK POTENTIOMETER TOTAL RESISTANCE
- Disconnect: HVAC Module - DATC C228a or HVAC Module - EMTC C2357a.
- Disconnect: Auxiliary Climate Controls C990 (If equipped).
- Measure the resistance between HVAC module - DATC C228a-11 or HVAC module - EMTC C2357a-11, circuit LH111 (BN/WH), harness side and HVAC module - DATC C228a-10 or HVAC module - EMTC C2357a-10, circuit RH111 (GY/BU), harness side.
- Is the resistance greater than 500 ohms?
Yes
GO to I3.
No
CARRY OUT the DEFROST/PANEL/FLOOR Mode 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. Defrost/Panel/Floor Door Actuator
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I3 CHECK THE POTENTIOMETER LOW- AND HIGH-SIDE RESISTANCE
- Measure the low-side resistance between HVAC module - DATC C228a-10 or HVAC module - EMTC C2357a-10, circuit RH111 (GY/BU), harness side and HVAC module - DATC C228a-8 or HVAC module - EMTC C2357a-8, circuit VH436 (YE/VT), harness side.
- Measure the high-side resistance between HVAC module - DATC C228a-11 or HVAC module - EMTC C2357a-11, circuit LH111 (BN/WH), harness side and HVAC module - DATC C228a-8 or HVAC module - EMTC C2357a-8, circuit VH436 (YE/VT), harness side.
- Are the resistances between 187 and 4,313 ohms?
Yes
GO to I4.
No
If the low-side resistance only is greater than 4,313 ohms, CARRY OUT the DEFROST/PANEL/FLOOR Mode Door Actuator Component Test. If the actuator tests OK, REPAIR circuit RH111 (GY/BU) for an open. CLEAR the DTCs. Defrost/Panel/Floor Door Actuator
REPEAT the self test. TEST the system for normal operation.
If the low-side resistance only is less than 187 ohms, CARRY OUT the DEFROST/PANEL/FLOOR Mode Door Actuator Component Test. If the actuator tests OK, REPAIR circuits VH436 (YE/VT) and RH111 (GY/BU) for a short together. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation. Defrost/Panel/Floor Door Actuator
If the high-side resistance only is greater than 4,313 ohms, CARRY OUT the DEFROST/PANEL/FLOOR Mode Door Actuator Component Test. If the actuator tests OK, REPAIR circuit LH111 (BN/WH) for an open. CLEAR the DTCs. Defrost/Panel/Floor Door Actuator
REPEAT the self test. TEST the system for normal operation.
If thehigh-side resistance only is less than 187 ohms, CARRY OUT the DEFROST/PANEL/FLOOR Mode Door Actuator Component Test. If the actuator tests OK, REPAIR circuits VH436 (YE/VT) and LH111 (BN/WH) for a short together. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation. Defrost/Panel/Floor Door Actuator
If thehigh-side and low-side resistance is greater than 4,313 ohms, CARRY OUT the DEFROST/PANEL/FLOOR Mode Door Actuator Component Test. If the actuator tests OK, REPAIR circuit VH436 (YE/VT) for an open. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation. Defrost/Panel/Floor Door Actuator
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I4 CHECK CIRCUIT LH111 (BN/WH) OR CIRCUIT VH436 (YE/VT) FOR A SHORT TO GROUND
- Disconnect: Defrost/Panel/Floor Door Actuator C2278.
- Measure the resistance between ground and the following:
- HVAC module - DATC C228a-11 or HVAC module - EMTC C2357a-11, circuit LH111 (BN/WH), harness side.
- HVAC module - DATC C228a-8 or HVAC module - EMTC C2357a-8, circuit VH436 (YE/VT), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to I5.
No
REPAIR circuit LH111 (BN/WH) or circuit VH436 (YE/VT) for a short to ground. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation.
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I5 CHECK CIRCUIT RH111 (GY/BU) OR CIRCUIT VH436 (YE/VT) FOR A SHORT TO POWER
- Ignition ON.
- Measure the voltage between ground and the following:
- HVAC module - DATC C228a-10 or HVAC module - EMTC C2357a-10, circuit RH111 (GY/BU), harness side.
- HVAC module - DATC C228a-8 or HVAC module - EMTC C2357a-8, circuit VH436 (YE/VT), harness side.
- Is any voltage present?
Yes
REPAIR circuit RH111 (GY/BU) or circuit VH436 (YE/VT) for a short to power. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation.
No
GO to I6.
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I6 CHECK THE 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 or HVAC module - EMTC C2357a-10, circuit RH111 (GY/BU), harness side and HVAC module - DATC C228a-8 or HVAC module - EMTC C2357a-8, circuit VH436 (YE/VT), harness side.
- Connect a fused jumper wire between:
- HVAC module - DATC C228a-23 or HVAC module - EMTC C2357a-23, circuit GD111 (BK/BU), harness side and HVAC module - DATC C228a-19 or HVAC module - EMTC C2357a-19, circuit CH229 (WH/BU), harness side.
- HVAC module - DATC C228a-13 or HVAC module - EMTC C2357a-13, circuit SBP15 (WH/RD), harness side and HVAC module - DATC C228a-20 or HVAC module - EMTC C2357a-20, circuit CH228 (YE/GY), harness side.
- Remove the fused jumpers.
- Connect a fused jumper wire between:
- HVAC module - DATC C228a-13 or HVAC module - EMTC C2357a-13, circuit SBP15 (WH/RD), harness side and HVAC module - DATC C228a-19 or HVAC module - EMTC C2357a-19, circuit CH229 (WH/BU), harness side.
- HVAC module - DATC C228a-23 or HVAC module - EMTC C2357a-23, circuit GD111 (BK/BU), harness side and HVAC module - DATC C228a-20 or HVAC module - EMTC C2357a-20, circuit CH228 (YE/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 I8.
No
GO to I7.
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I7 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: Defrost/Panel/Floor Door Actuator C2278.
- Measure the resistance between HVAC module - DATC C228a-19 or HVAC module - EMTC C2357a-19, circuit CH229 (WH/BU), harness side and floor/defrost/panel door actuator C2278-1, circuit CH229 (WH/BU), harness side.
- Measure the resistance between HVAC module - DATC C228a-20 or HVAC module - EMTC C2357a-20, circuit CH228 (YE/GY), harness side and defrost/panel/floor door actuator C2278-6, circuit CH228 (YE/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 CH228 (YE/GY) or circuit CH229 (WH/BU) for an open. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation.
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I8 CHECK THE MODULE CONNECTION
- Carry out the HVAC Module Cold Boot Process. HVAC Module Cold Boot Process
- NOTE: DATC systems only.
- 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. 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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