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 solid state relay.
3. Test for less than 5 ohm between the ground circuit terminal B and ground.
锟斤拷If greater than the specified range, test the ground circuit for an open/high resistance.
4. Ignition OFF, verify that a test lamp illuminates between the B+ circuit terminal F and ground.
锟斤拷If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the
STUD 2 fuse is open, replace the trailer brake control relay.
5. Ignition ON, verify that a test lamp does not illuminate between control circuit terminal E and ground.
锟斤拷If test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the trailer brake control module.
6. Ignition ON, verify that a test lamp does not illuminate between control circuit terminal E and B+.
锟斤拷If test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the trailer brake control module.
7. Ignition ON, test for 3.2-4.1 V between the control circuit terminal C and ground.
锟斤拷If less than the specified range, test the control 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 control circuit for a short to voltage. If the circuit tests normal, replace the trailer brake control
module.
8. Ignition ON, test for 3.2-4.1 V between the control circuit terminal A and ground.
锟斤拷If less than the specified range, test the control 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 control circuit for a short to voltage. If the circuit tests normal, replace the trailer brake control
module.
9. Ignition ON, test for less than 1 V between the control circuit terminal D and ground.
锟斤拷If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the trailer brake control
module.
10. If all circuits test normal, replace the trailer brake solid state relay.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
