Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Trailer Brake Controls Description and Operation (See: Powertrain Management/Computers and Control Systems/Description and
Operation/Trailer Brake Controls Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
Ignition ON, observe the scan tool trailer brake controls user gain parameter. The reading should be between 0-100 percent, and change with
operating the gain switch up or gain switch down.
Circuit/System Testing
Note: These diagnostics are based on having no trailer connected.
1. Ignition ON, verify that DTC P2534 is not set.
锟斤拷If the DTC is set, refer to DTC P2534 (See: P Code Charts/P2534/Wiring Systems and Power Management).
2. Ignition OFF, disconnect the harness connector at the trailer brake controller switch.
3. Test for less than 5 ohm between the low reference circuit terminal 8 and ground.
锟斤拷If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the fuel
pump/trailer brake control module.
4. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground.
锟斤拷If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal,
replace the fuel pump/trailer brake control module.
锟斤拷If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the fuel
pump/trailer brake control module.
5. Verify the scan tool Manual Apply Switch parameter is less than 5 percent.
锟斤拷If greater than the specified range, test the signal circuit terminal 4 for a short to voltage. If the circuit tests normal, replace the fuel
pump/trailer brake control module.
6. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the 5 V reference circuit terminal 3. Verify the scan tool Manual
Apply Switch parameter is greater than 90 percent.
锟斤拷If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace
the fuel pump/trailer brake control module.
7. Verify the scan tool Redundant Manual Apply Switch parameter is greater than 90 percent.
锟斤拷If less than the specified range, test the signal circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the fuel
pump/trailer brake control module.
8. Install a 3 A fused jumper wire between the signal circuit terminal 5 and the 5 V reference circuit terminal 3. Verify the scan tool Redundant
Manual Apply Switch parameter is less than 2 percent.
锟斤拷If greater than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal,
replace the fuel pump/trailer brake control module.
