Test No. 20: All Power Windows Will Not Operate
- Check DOOR fuse (20-amp) and POWER fuse (30-amp). Fuses are located in fuse/relay box at driver's side of instrument panel. See Figure. If fuses are okay, go to next step. If any fuse is defective, repair short in wiring for appropriate fuse. See WIRING DIAGRAMS in POWER WINDOWS - TRUCKS article. For additional wiring for power supply circuit, see POWER DISTRIBUTION article in WIRING DIAGRAMS. Passenger's side Junction Block (J/B) Electronic Control Unit (ECU) is located at passenger's side of instrument panel. See Figure. Power window master switch is located on driver's door. See Figure.
- Check ignition switch. See IGNITION SWITCH under COMPONENT TESTS. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch and recheck power window operation. See IGNITION SWITCH under REMOVAL & INSTALLATION.
- Check power window master switch. See POWER WINDOW MASTER SWITCH under COMPONENT TESTS. If power window master switch is okay, go to next step. If power window master switch is defective, replace power window master switch and recheck power window operation.
- Check wiring harness and electrical connectors for power window master switch, power window switches and power window motors. See WIRING DIAGRAMS in POWER WINDOWS - TRUCKS article. It may be necessary to operation of check power relay. See POWER RELAY under COMPONENT TESTS. It may be necessary to check wiring harness and electrical connectors between passenger's side Junction Block (J/B) Electronic Control Unit (ECU) and power relay, and between power relay and power window switch. See WIRING DIAGRAMS in POWER WINDOWS - TRUCKS article. Passenger's side J/B ECU is located at passenger's side of instrument panel. See Figure. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary and recheck power window operation.
- Check passenger's side J/B ECU for proper voltage and input signals. See PASSENGER'S SIDE JUNCTION BLOCK ELECTRONIC CONTROL UNIT under PIN VOLTAGE TESTS. If proper voltage and input signals exist, go to next step. If proper voltage and input signals do not exist, repair as necessary and recheck power window operation.
- Replace passenger's side J/B ECU with a known-good passenger's side J/B ECU and recheck power window operation. If power windows operate properly, original passenger's side J/B ECU was defective. If power windows still do not operate properly, check wiring harness and electrical connectors for passenger's side J/B ECU, power relay and power windows for intermittent problem. See WIRING DIAGRAMS in POWER WINDOWS - TRUCKS article. Repair wiring harness or electrical connector as necessary.