2. Ignition OFF, disconnect the harness connector of the fuel pump/trailer brake control module.
3. Ignition ON, test for greater than 11 V between the IGN 1 voltage circuit terminal 15 and ground.
锟斤拷 If less than the specified voltage, test the IGN 1 voltage circuit for a short to ground or an open/high resistance. If the circuit test normal
and the MISC - IGN fuse is open, test the signal circuit terminal 37 for a short to ground. If the circuit tests normal, test or replace the
RUN/CRANK relay.
4. If all the circuits test normal, replace the fuel pump/trailer brake control module.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Relay Replacement (Attached to Wire Harness) (See: Power and Ground Distribution/Power Distribution Relay/Service and Repair/Relay
Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (See: Power and Ground Distribution/Power
Distribution Relay/Service and Repair/Relay Replacement (Within an Electrical Center))
* Control Module References (See: Testing and Inspection/Programming and Relearning) for fuel pump/trailer brake control module
replacement, setup, and programming
B3920
DTC B3920 or B3921
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC B3920 01
- Group 1 Seat Motors Common Circuit Short to Battery
DTC B3920 02
- Group 1 Seat Motors Common Circuit Short to Ground
DTC B3921 01
- Group 2 Seat Motors Common Circuit Short to Battery
DTC B3921 02
- Group 2 Seat Motors Common Circuit Short to Ground
Diagnostic Fault Information
