Pinpoint Test AE: The Trailer Electric Brakes Are Inoperative/Do Not Operate Correctly
Trailer Lamps
Pinpoint Test AE: The Trailer Electric Brakes Are Inoperative/Do Not Operate Correctly
Normal Operation
The Trailer Brake Control (TBC) module is provided voltage at all times by the Battery Junction Box (BJB) fuse 3 (30A). The TBC (Trailer Brake Control) module receives voltage from the stoplamp switch when the brake pedal is applied. When a brake application is detected from the stoplamp switch, the TBC (Trailer Brake Control) module sends voltage to the trailer tow connector.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Trailer tow connector
- TBC (Trailer Brake Control) module
- Trailer
PINPOINT TEST AE : THE TRAILER ELECTRIC BRAKES ARE INOPERATIVE/DO NOT OPERATE CORRECTLY
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Before beginning diagnostics, visually inspect the trailer tow connector mounted on the bumper for signs of corrosion or damage. Repair or install a new trailer tow connector as required.
AE1 CHECK THE TBC (Trailer Brake Control) MODULE FOR A SHORTED OUTPUT
- Ignition ON.
- Measure the voltage between the trailer tow connector electric brake control supply pin, circuit CAT19 (BU), component side and ground.
Is any voltage present?
Yes
GO to AE2.
No
GO to AE3.
AE2 CHECK THE TBC (Trailer Brake Control) MODULE OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: TBC (Trailer Brake Control) Module C2142.
- Measure the voltage between the trailer tow connector electric brake control supply pin, circuit CAT19 (BU), component side and ground.
Is any voltage present?
Yes
REPAIR circuit CAT19 (BU) for a short to voltage. TEST the system for normal operation.
No
INSTALL a new TBC (Trailer Brake Control) module. TEST the system for normal operation.
AE3 CHECK THE TBC (Trailer Brake Control) MODULE OUTPUT
- Set the gain on the TBC (Trailer Brake Control) module to the maximum setting.
- While applying the brake pedal, measure the voltage between the trailer tow connector electric brake control supply pin, circuit CAT19 (BU), component side and ground.
Is the voltage greater than 10 volts?
Yes
The vehicle is operating correctly. SEND the trailer to an authorized camper/trailer repair facility.
No
GO to AE4.
AE4 CHECK FOR VOLTAGE TO THE TRAILER TOW CONNECTOR
- Disconnect: Trailer Tow C4099.
- NOTE: Make sure the gain is set to the maximum setting.
While applying the brake pedal, measure the voltage between the trailer tow C4099-3, circuit CAT19 (BU), harness side and ground.
Is the voltage greater than 10 volts?
Yes
INSTALL a new trailer tow connector. TEST the system for normal operation.
No
GO to AE5.
AE5 CHECK THE TBC (Trailer Brake Control) MODULE VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Disconnect: TBC (Trailer Brake Control) Module C2142.
- Measure the voltage between the TBC (Trailer Brake Control) module C2142-1, circuit CAT18 (YE/OG), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to AE6.
No
VERIFY the BJB (Battery Junction Box) fuse 3 (30A) is OK. If OK, REPAIR circuit CAT18 (YE/OG) for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Electrical Diagrams
AE6 CHECK THE STOPLAMP SWITCH INPUT CIRCUIT FOR AN OPEN
- While applying the brake pedal, measure the voltage between the TBC (Trailer Brake Control) module C2142-2, circuit CCB08 (VT/WH), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to AE7.
No
REPAIR circuit CCB08 (VT/WH) for an open. TEST the system for normal operation.
AE7 CHECK FOR VOLTAGE TO THE TBC (Trailer Brake Control) MODULE USING THE CONNECTOR GROUND
- Measure the voltage between the TBC (Trailer Brake Control) module C2142-1, circuit CAT18 (YE/OG), harness side and the TBC (Trailer Brake Control) module C2142-6, circuit RAT08 (WH), harness side.
Is the voltage greater than 10 volts?
Yes
GO to AE8.
No
REPAIR circuit RAT08 (WH) for an open. TEST the system for normal operation.
AE8 CHECK THE TBC (Trailer Brake Control) MODULE OUTPUT CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between the TBC (Trailer Brake Control) module C2142-3, circuit CAT19 (BU), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to AE9.
No
REPAIR circuit CAT19 (BU) for a short to ground. TEST the system for normal operation.
AE9 CHECK THE TBC (Trailer Brake Control) MODULE OUTPUT CIRCUIT FOR AN OPEN
- Connect a fused jumper wire between the TBC (Trailer Brake Control) module C2142-1, circuit CAT18 (YE/OG), harness side and the TBC (Trailer Brake Control) module C2142-3, circuit CAT19 (BU), harness side.
- Measure the voltage between the trailer tow C4099-3, circuit CAT19 (BU), harness side and ground.
Is the voltage greater than 10 volts?
Yes
REMOVE the jumper wire. INSTALL a new TBC (Trailer Brake Control) module. TEST the system for normal operation.
No
REMOVE the jumper wire. REPAIR circuit CAT19 (BU) for an open. TEST the system for normal operation.