Pinpoint Test H: The Air Inlet Door Is Inoperative

Climate Control System

Pinpoint Tests

Pinpoint Test H: The Air Inlet Door is Inoperative

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 air inlet door actuator clockwise, the HVAC module supplies voltage to the air inlet mode door actuator through the circuit CH207 (BU/GY), and supplies ground through circuit CH208 (GN/OG). To rotate the air inlet mode door actuator counterclockwise, the HVAC module reverses the voltage and ground circuits.

NOTE: Dual Automatic Temperature Control (DATC) only.

The air inlet mode 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 air inlet mode door actuator feedback circuit VH438 (GN/VT) to determine the air inlet mode door actuator position by the position of the actuator feedback resistor wiper arm.

- DTC B1242 Air Flow Recirculation Door Driver Circuit 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
- Air inlet mode door actuator
- HVAC module - DATC
- HVAC module - Electronic Manual Temperature Control (EMTC)
- Stuck or bound linkage or door

PINPOINT TEST H: THE AIR INLET DOOR IS INOPERATIVE

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H1 CHECK FOR DATC

- Observe the climate controls.
- Is the vehicle equipped with DATC?

Yes
GO to H2.

No
GO to H7.

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H2 CHECK THE FEEDBACK POTENTIOMETER TOTAL RESISTANCE

- Ignition OFF.
- Disconnect: HVAC Module - DATC C228a.
- Disconnect: HVAC Module - DATC C228b.
- Disconnect: Auxiliary Climate Controls C990 (If equipped).
- Measure the resistance between HVAC module - DATC C228a-11, circuit LH111 (BN/WH), harness side and HVAC module - DATC C228a-10, circuit RH111 (GY/BU), harness side.

- Is the resistance greater than 500 ohms?

Yes
GO to H3.

No
CARRY OUT the Air Inlet 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. Air Inlet Door Mode Actuator

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H3 CHECK POTENTIOMETER HIGH- AND LOW-SIDE RESISTANCE

- Measure the low-side resistance between HVAC module - DATC C228a-10, circuit RH111 (GY/BU), harness side and HVAC module - DATC C228b-15, circuit VH438 (GN/VT), harness side.

- Measure the high-side resistance between HVAC module - DATC C228a-11, circuit LH111 (BN/WH), harness side and HVAC module - DATC C228b-15, circuit VH438 (GN/VT), harness side.

- Is the resistance between 120 and 4,380 ohms?

Yes
GO to H4.

No
If the low-side resistance only is greater than 4,380 ohms, CARRY OUT the Air Inlet Mode 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. Air Inlet Door Mode Actuator

If the low-side resistance only is less than 120 ohms, CARRY OUT the Air Inlet Mode Door Actuator Component Test. If the actuator tests OK, REPAIR circuits VH438 (GN/VT) and RH111 (GY/BU) for a short together. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation. Air Inlet Door Mode Actuator

If the high-side resistance only is greater than 4,380 ohms, CARRY OUT the Air Inlet Mode 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. Air Inlet Door Mode Actuator

If thehigh-side resistance only is less than 120 ohms, CARRY OUT the Air Inlet Mode Door Actuator Component Test. If the actuator tests OK, REPAIR circuits VH438 (GN/VT) and LH111 (BN/WH) for a short together.
CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation. Air Inlet Door Mode Actuator

If thehigh-side and low-side resistance is greater than 4,380 ohms, CARRY OUT the Air Inlet Mode Door Actuator Component Test. If the actuator tests OK, REPAIR circuit VH438 (GN/VT) for an open. CLEAR the DTCs. Air Inlet Door Mode Actuator
REPEAT the self test. TEST the system for normal operation.

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H4 CHECK CIRCUIT LH111 (BN/WH) OR VH438 (GN/VT) 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-15, circuit VH438 (GN/VT), harness side.

- Are the resistances greater than 10,000 ohms?

Yes
GO to H5.

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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H5 CHECK CIRCUIT RH111 (GY/BU) OR VH438 (GN/VT) 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-15, circuit VH438 (GN/VT), harness side.

- Are any voltages 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 H6.

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H6 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-15, circuit VH438 (GN/VT), harness side.

- Connect a fused jumper wire between:
- HVAC module - EMTC C2357a-15 or HVAC module - DATC C228a-15, circuit CH208 (GN/OG), harness side and HVAC module - EMTC C2357a-23 or HVAC module - DATC C228a-23, circuit GD111 (BK/BU), harness side.
- HVAC module - EMTC C2357a-16 or HVAC module - DATC C228a-16, circuit CH207 (BU/GY), harness side and HVAC module - EMTC C2357a-13 or HVAC module - DATC C228a-13, circuit SBP15 (WH/RD), harness side.

- Remove the fused jumpers.
- Connect a fused jumper wire between:
- HVAC module - EMTC C2357a-15 or HVAC module - DATC C228a-15, circuit CH208 (GN/OG), harness side and HVAC module - EMTC C2357a-13 or HVAC module - DATC C228a-13, circuit SBP15 (WH/RD), harness side.
- HVAC module - EMTC C2357a-16 or HVAC module - DATC C228a-16, circuit CH207 (BU/GY), harness side and HVAC module - EMTC C2357a-23 or HVAC module - DATC C228a-23, circuit GD111 (BK/BU), harness side.

- Does the resistance smoothly increase and/or decrease when the jumpers are connected?

Yes
INSPECT for binding or broken door and linkage. REPAIR as necessary. If no condition is found, GO to H9.

No
GO to H8.

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H7 CHECK DOOR ACTUATOR OPERATION

NOTE: If a jumper fuse opens while carrying out this test step, repair the circuit(s) for a short.

- Ignition OFF.
- Disconnect: HVAC Module - EMTC C2357a.
- Connect: Air Inlet Mode Door Actuator C289 (if previously disconnected).
- Remove the door actuator and disengage the actuator driveshaft from the actuator door.
- Mark the door actuator driveshaft position.
- Observe the actuator driveshaft.
- Ignition ON.
- Connect a fused jumper wire between:
- HVAC module - EMTC C2357a-15 or HVAC module - DATC C228a-15, circuit CH208 (GN/OG), harness side and HVAC module - EMTC C2357a-23 or HVAC module - DATC C228a-23, circuit GD111 (BK/BU), harness side.
- HVAC module - EMTC C2357a-16 or HVAC module - DATC C228a-16, circuit CH207 (BU/GY), harness side and HVAC module - EMTC C2357a-13 or HVAC module - DATC C228a-13, circuit SBP15 (WH/RD), harness side.

- Does the actuator motor rotate in both directions?

Yes
INSPECT for binding or broken door and linkage. REPAIR as necessary. If no condition is found, GO to H9.

No
GO to H8.

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H8 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR AN OPEN

- Disconnect: Air Inlet Door Actuator C289.
- Measure the resistance between HVAC module - EMTC C2357a-16 or HVAC module - DATC C228a-16, circuit CH207 (BU/GY), harness side and air inlet mode door actuator C289-6, circuit CH207 (BU/GY), harness side.

- Measure the resistance between HVAC module - EMTC C2357a-15 or HVAC module - DATC C228a-15, circuit CH208 (GN/OG), harness side and air inlet mode door actuator C289-5, circuit CH208 (GN/OG), 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 air inlet mode door actuator. TEST the system for normal operation.

No
REPAIR the circuit(s) for an open. TEST the system for normal operation.

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H9 CHECK 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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