Pinpoint Test AE: The Trailer Electric Brakes Are Inoperative/Do Not Operate Correctly
Trailer Lamps
Pinpoint Tests
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 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 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 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 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 MODULE OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: TBC 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 module. TEST the system for normal operation.
-------------------------------------------------
AE3 CHECK THE TBC MODULE OUTPUT
- Set the gain on the TBC 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 MODULE VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Disconnect: TBC Module C2142.
- Measure the voltage between the TBC 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 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. Diagrams By Number
-------------------------------------------------
AE6 CHECK THE STOPLAMP SWITCH INPUT CIRCUIT FOR AN OPEN
- While applying the brake pedal, measure the voltage between the TBC 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 MODULE USING THE CONNECTOR GROUND
- Measure the voltage between the TBC module C2142-1, circuit CAT18 (YE/OG), harness side and the TBC 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 MODULE OUTPUT CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between the TBC 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 MODULE OUTPUT CIRCUIT FOR AN OPEN
- Connect a fused jumper wire between the TBC module C2142-1, circuit CAT18 (YE/OG), harness side and the TBC 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 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.
-------------------------------------------------