Speed Control Does Not Disengage When Brakes Are Applied
WARNING:
Disable air bag system before working around steering column or removing any air bag system component. See AIR BAG RESTRAINT SYSTEM article.
- Check Stoplights - Depress and release brake pedal several times, and check stoplight operation. If stoplights are okay, go to next step. If stoplight are not okay, see appropriate EXTERIOR LIGHTS wiring diagram in SYSTEM WIRING DIAGRAMS article in the WIRING DIAGRAMS section to continue diagnosis.
- Check Brake On/Off (BOO) Switch - Turn ignition off. Disconnect speed control amplifier connector C247. Depress brake pedal. Using a voltmeter, check voltage between ground and speed control amplifier connector C247 Yellow wire terminal. Release brake pedal. Check voltage between ground and speed control amplifier connector C247 Yellow wire terminal. If voltage is more than 10 volts with brake pedal depressed, and less than one volt with brake pedal released, go to next step. If voltage is not more than 10 volts with brake pedal depressed, and less than one volt with brake pedal released, repair Yellow wire and retest system operation.
- Check Speed Control Disengage Switch - Turn ignition off. Reconnect speed control amplifier connector. Disconnect speed control disengage switch connector C278. Using an ohmmeter, check resistance between Blue and White wires of speed control disengage switch connector C278 with brake pedal depressed. Resistance should be more than 10 k/ohms. Check resistance between Blue and White wires of speed control disengage switch connector C278 with brake pedal released. Resistance should be less than 5 ohms. If resistances are as specified, replace speed control amplifier and retest system operation. If resistances are not as specified, replace speed control disengage switch and retest system operation.