Pinpoint Test N: Temperature Control Is Inoperative/Does Not Operate Correctly

Climate Control System

Pinpoint Tests

Pinpoint Test N: Temperature Control is Inoperative/Does Not Operate Correctly

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 blend door actuator clockwise, 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 rotate the blend door actuator counterclockwise, 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
- LH blend - CH238 (YE/OG)
- RH blend - CH212 (BU/OG)

Door actuator feed B circuits
- LH blend - CH239 (BU/WH)
- 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
- LH blend - VH440 (BU/BN)
- RH blend - VH411 (VT/GN)

- DTC B2266 LH Blend Door Failure or Short - The module senses no change in actuator feedback voltage when the actuator motor has been energized.
- DTC B2267 RH Blend Door Failure or Short - 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
- Blend door actuator
- HVAC module - Dual Automatic Temperature Control (DATC)
- HVAC module - Electronic Manual Temperature Control (EMTC)
- Stuck or bound linkage or door

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

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N1 CHECK THE FEEDBACK POTENTIOMETER TOTAL RESISTANCE

- Disconnect: HVAC Module - DATC C228a or HVAC Module - EMTC C2357a.
- Disconnect: HVAC Module - DATC C228b.
- 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 N2.

No
CARRY OUT the Blend 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. Component Tests and General Diagnostics

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N2 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 the following:
- For DTC B2266, HVAC module - DATC C228a-7 or HVAC module - EMTC C2357a-7, circuit VH440 (BU/BN), harness side.
- For DTC B2267, HVAC module - DATC C228b-24, circuit VH411 (VT/GN), 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 the following:
- For DTC B2266, HVAC module - DATC C228a-7 or HVAC module - EMTC C2357a-7, circuit VH440 (BU/BN), harness side.
- For DTC B2267, HVAC module - DATC C228b-24, circuit VH411 (VT/GN), harness side.

- Are the resistances between 120 and 4,380 ohms?

Yes
GO to N3.

No
If the low-side resistance only is greater than 4,380 ohms, CARRY OUT the Blend 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. Component Tests and General Diagnostics

If the low-side resistance only is less than 120 ohms, CARRY OUT the Blend Door Actuator Test. If the actuator tests OK, REPAIR circuit VH440 (BU/BN) or VH411 (VT/GN) for a short to circuit RH111 (GY/BU). CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation. Component Tests and General Diagnostics

If the high-side resistance only is greater than 4,380 ohms, CARRY OUT the Blend 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. Component Tests and General Diagnostics

If thehigh-side resistance only is less than 120 ohms, CARRY OUT the Blend Door Actuator Component Test. If the actuator tests OK, REPAIR circuits circuit VH440 (BU/BN) or VH411 (VT/GN) for a short to circuit LH111
(BN/WH). CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation. Component Tests and General Diagnostics

If thehigh-side and low-side resistance is greater than 4,380 ohms, CARRY OUT the Blend Door Actuator Component Test. If the actuator tests OK, REPAIR circuit VH440 (BU/BN) or VH411 (VT/GN) for an open. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation. Component Tests and General Diagnostics

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N3 CHECK CIRCUITS LH111 (BN/WH), VH440 (BU/BN) OR VH411 (VT/GN) FOR A SHORT TO GROUND

- 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.
- For DTC B2266, HVAC module - DATC C228a-7 or HVAC module - EMTC C2357a-7, circuit VH440 (BU/BN), harness side.
- For DTC B2267, HVAC module - DATC C228b-24, circuit VH411 (VT/GN), harness side.

- Are the resistances greater than 10,000 ohms?

Yes
GO to N4.

No
REPAIR circuit LH111 (BN/WH), VH411 (VT/GN) or VH440 (BU/BN) for a short to ground. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation.

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N4 CHECK CIRCUITS RH111 (GY/BU), VH440 (BU/BN) OR VH411 (VT/GN) 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.
- For DTC B2266, HVAC module - DATC C228a-7 or HVAC module - EMTC C2357a-7, circuit VH440 (BU/BN), harness side.
- For DTC B2267, HVAC module - DATC C228b-24, circuit VH411 (VT/GN), harness side.

- Are any voltages present?

Yes
REPAIR circuits RH111 (GY/BU), VH411 (VT/GN) or VH440 (BU/BN) for a short to power. CLEAR the DTCs. REPEAT the self test. TEST the system for normal operation.

No
For DTC B2266, GO to N5.

For DTC B2267, GO to N6.

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N5 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-7 or HVAC module - EMTC C2357a-7, circuit VH440 (BU/BN), harness side.

- 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-22 or HVAC module - EMTC C2357a-22, circuit CH238 (YE/OG), harness side.
- HVAC module - DATC C228a-23 or HVAC module - EMTC C2357a-23, circuit GD111 (BK/BU), harness side and HVAC module - DATC C228a-21 or HVAC module - EMTC C2357a-21, circuit CH239 (BU/WH), harness side.

- Remove the fused jumpers.
- 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-22 or HVAC module - EMTC C2357a-22, circuit CH238 (YE/OG), harness side.
- HVAC module - DATC C228a-13 or HVAC module - EMTC C2357a-13, circuit SBP15 (WH/RD), harness side and HVAC module - DATC C228a-21 or HVAC module - EMTC C2357a-21, circuit CH239 (BU/WH), harness side.

- Connect a fused jumper wire between:
- HVAC module - DATC C228b-13, circuit SBP15 (WH/RD), harness side and HVAC module - DATC C228b-26, circuit CH212 (BU/OG), harness side.
- HVAC module - DATC C228a-23, circuit GD111 (BK/BU), harness side and HVAC module - DATC C228b-25, circuit CH213 (BN/GN), 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-26, circuit CH212 (BU/OG), harness side.
- HVAC module - DATC C228a-13, circuit SBP15 (WH/RD), harness side and HVAC module - DATC C228b-25, circuit CH213 (BN/GN), 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 N8.

No
GO to N7.

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N7 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: For DTC B2266, LH Blend Door Actuator C2091.
- Disconnect: For DTC B2267, RH Blend Door Actuator C2092.
- Measure the resistance between:
- For DTC B2266, HVAC module - DATC C228a-22 or HVAC module - EMTC C2357a-22, circuit CH238 (YE/OG), harness side and LH blend door actuator C2091-6, circuit CH238 (YE/OG), harness side.
- For DTC B2267, HVAC module - DATC C228b-26, circuit CH212 (BU/OG), harness side and RH blend door actuator C2092-6, circuit CH212 (BU/OG), harness side.

- Measure the resistance between:
- For DTC B2266, HVAC module - DATC C228a-21 or HVAC module - EMTC C2357a-21, circuit CH239 (BU/WH), harness side and LH blend door actuator C2091-5, circuit CH239 (BU/WH), harness side.
- For DTC B2267, HVAC module - DATC C228b-25, circuit CH213 (BN/GN), harness side and RH blend door actuator C2092-5, circuit CH213 (BN/GN), 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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N8 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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