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 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 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 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 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 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 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 trailer brake control module.
9. Ignition ON, test for 4.8-5.2 V between the signal circuit terminal 6 and ground.
