Pinpoint Test C: The Tow/Haul Switch Is Not Operating Correctly

External Controls

Pinpoint Tests

PINPOINT TEST C: THE TOW/HAUL SWITCH IS NOT OPERATING CORRECTLY

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C1 CHECK THE BCM FUSE 35 (5A)

- Ignition OFF.
- Remove Body Control Module (BCM) fuse 35 (5A).
- Check fuse: BCM 35 (10A).
- Is the resistance less than 5 ohms?

Yes
REINSTALL the fuse. GO to C5.

No
GO to C2.

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C2 CHECK THE BCM FOR AN INTERNAL SHORT

- Disconnect: BCM C2280B.
- Inspect for damaged or pushed-out terminals, corrosion or loose wires. Repair as necessary.
- Install a new fuse.
- Did the fuse fail?

Yes
INSTALL a new BCM. REFER to Multifunction Electronic Modules Service and Repair. RECONNECT all components. TEST the system for normal operation.

No
GO to C3.

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C3 CHECK THE TOW/HAUL SWITCH POWER CIRCUIT FOR A SHORT TO GROUND

- Disconnect: Tow/Haul Switch C2399.
- Disconnect: Parking Aid Module (PAM) C2023.
- Disconnect: Trailer Brake Control (TBC) C2142.
- Inspect for damaged or pushed-out terminals, corrosion or loose wires. Repair as necessary.
- Measure the resistance between tow/haul switch C2399-1, circuit CBP35 (YE/GY), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to C4.

No
REPAIR circuit CBP35 (YE/GY) for a short to ground. RECONNECT all components. TEST the system for normal operation.

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C4 CHECK THE TOW/HAUL SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND

- Disconnect: PCM C175T.
- Disconnect: Transmission Control Module (TCM) C1750.
- For gasoline engine vehicles, measure the resistance between PCM C175T-33, circuit CAT15 (BN/YE), harness side and ground.




- For diesel engine vehicles, measure the resistance between TCM C1750-53, circuit CAT15 (BN/YE), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to C5.

No
REPAIR circuit CAT15 (BN/YE) for a short to ground. RECONNECT all components. TEST the system for normal operation.

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C5 CHECK THE TOW/HAUL SWITCH POWER CIRCUIT FOR AN OPEN

- Disconnect: Tow/Haul Switch C2399 .
- Measure the resistance between tow/haul switch C2399-1, circuit CBP35 (YE/GY), harness side and BCM C2280-7, circuit CBP35 (YE/GY), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to C6.

No
REPAIR circuit CBP35 (YE/GY) for an open. RECONNECT all components. TEST the system for normal operation.

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C6 CHECK THE TOW/HAUL SWITCH INPUT CIRCUIT FOR AN OPEN

- Disconnect: PCM C175T .
- Disconnect: TCM C1750 .
- For gasoline engine vehicles, measure the resistance between tow/haul switch C2399-2, circuit CAT15 (BN/YE), harness side and PCM C175T-33, circuit CAT15 (BN/YE), harness side.




- For diesel engine vehicles, measure the resistance between tow/haul switch C2399-2, circuit CAT15 (BN/YE), harness side and TCM C1750-53, circuit CAT15 (BN/YE), harness side.




- Is the resistance less than 5 ohms for all circuits?

Yes
GO to C7.

No
REPAIR circuit CAT15 (BN/YE) for an open. RECONNECT all components. TEST the system for normal operation.

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C7 CHECK THE TOW/HAUL SWITCH

- Measure the resistance between tow/haul switch C2399-1 and tow/haul switch C2399-2, component side while pressing and releasing the switch.




- Is the resistance less than 5 ohms with the switch pressed, and greater than 10,000 ohms with the switch released?

Yes
GO to C8.

No
INSTALL a new selector lever, REFER to Selector Lever Selector Lever.

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C8 CHECK THE PCM OR TCM

- Connect: BCM C2280B .
- Connect: Tow/Haul Switch C2399 .
- Ignition ON.
- For gasoline engine vehicles, measure the voltage at PCM C175T-33, circuit CAT15 (BN/YE), harness side, while pressing and releasing the switch.




- For diesel engine vehicles, measure the voltage at TCM C1750-53, circuit CAT15 (BN/YE), harness side, while pressing and releasing the switch.




- Is the voltage greater than 10 volts with the switch pressed, and less than 5 volts with the switch released?

Yes
INSTALL a new PCM or TCM. PROGRAM the PCM or TCM with the latest calibration level. If the vehicle is equipped with the TorqShift(R)6, PERFORM the solenoid strategy download procedure, REFER to solenoid body strategy in Automatic Transaxle/Transmission - TorqShift(R)6 Solenoid Body Strategy - TorqShift(R)6. TEST the system for normal operation.

No
REPAIR circuit CAT15 (BN/YE) for an open. RECONNECT all components. TEST the system for normal operation.

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