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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 30 (HVAC SYSTEMS - AUTOMATIC)SYMPTOM TESTSTEST M: STEERING WHEEL CONTROLS ARE INOPERATIVE
1999 GMC Forward Control 5.7 R, Automatic

Test M: Steering Wheel Controls Are Inoperative

1999 GMC Forward Control 5.7 R, AutomaticSECTION Test M: Steering Wheel Controls Are Inoperative
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
WARNING: Vehicle is equipped with Supplemental Inflatable Restraint (SIR) system. When servicing vehicle, use care to avoid accidental air bag deployment. SIR system-related components are located in various locations throughout interior and exterior of vehicle, depending on application. Do not use electrical test equipment on or near these circuits. If necessary, deactivate SIR system before servicing components. See DISABLING & ACTIVATING AIR BAG SYSTEM article in RESTRAINTS.
  1. Perform diagnostic system check. See DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing system check, go to next step.
  2. Connect scan tool. Turn ignition on, engine off. Observe STEERING WHEEL CONTROLS parameter in DASH INTEGRATION MODULE data list. Press each HVAC switch in both directions. If counts change for any switch pressed, go to next step. If counts do not change with any switch pressed, go to step  5.
  3. Use scan tool to observe STEERING WHEEL CONTROLS parameter. Press each radio and HVAC switch in both directions. If counts change for all switches pressed, go to next step. If counts do not change for each switch pressed, go to step  9.
  4. Turn on radio, increase and decrease volume with right controls switch on steering wheel. If radio function is controlled with steering wheel switches, see TEMPERATURE IS TOO COLD IN VEHICLE  and/or TEMPERATURE IS TOO HOT IN VEHICLE  . If radio function is not controlled with steering wheel switches, go to step  11.
  5. Deactivate air bag system. Turn ignition off. Remove and disconnect steering wheel controls. See STEERING WHEEL CONTROL SWITCHES  under REMOVAL & INSTALLATION. Turn ignition on, engine off. Connect a 3 amp fused jumper wire between terminals No. 1 and No. 5 (Dark Blue wires) of left steering wheel controls harness connector. If counts change, go to step  10. If counts do not change, go to next step.
  6. Measure voltage between ground and terminal No. 1 (Purple wire) of right steering wheel control switch harness connector. If battery voltage exists, go to next step. If battery voltage does not exist, go to step  8.
  7. Check continuity of Dark Blue wire between terminal A1 of Dash Integration Module (DIM) and terminal No. 5 of left steering wheel control switch. If continuity does not exist, repair open, short to ground, short to voltage, or high resistance in Dark Blue wire. When repair is complete, go to step  15. If continuity exists, go to step  12.
  8. Check remote radio control supply voltage circuit of right Steering Wheel Controls for an open or short to ground. See WIRING DIAGRAMS . If open or short to ground is found, repair as necessary. When repair is complete, go to step  15. If open or short to ground is not found, go to step  12.
  9. Check remote radio control supply voltage circuit of left Steering Wheel Controls for an open or short to ground. See WIRING DIAGRAMS . If open or short to ground is found, repair as necessary. When repair is complete, go to step  15. If open or short to ground is not found, go to step  10.
  10. Check for loose or poor connections at left Steering Wheel Controls harness connector. If poor connection is found, repair as necessary. When repair is complete, go to step  15. If loose connection is not found, go to step  13.
  11. Check left and right Steering Wheel Control switches of remote radio control head supply voltage circuit for a short to voltage. See WIRING DIAGRAMS . If short to voltage is found, repair as necessary. When repair is complete, go to step  15. If short to voltage is not found, go to next step
  12. Check for loose wires and/or poor connections at DIM harness connector. If poor connection is found, repair as necessary. When repair is complete, go to step  15. If loose connection is not found, go to step  13.
  13. Replace left steering wheel control switch. See STEERING WHEEL CONTROL SWITCHES  under REMOVAL & INSTALLATION. When repair is complete, go to step  15.
  14. Replace DIM. See DASH INTEGRATION MODULE (DIM)  under REMOVAL & INSTALLATION. When repair is complete, go to step  15.
  15. Enable SIR system. See DISABLING & ACTIVATING AIR BAG SYSTEM procedures in AIR BAG RESTRAINT SYSTEMS article in AIR BAG under RESTRAINTS.
  16. Operate system to verify repair. If condition is corrected, system is okay. If condition is not corrected, go to step  2.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.