Cruise Control, Pcm, AEROSTAR EIC, Or Electronic Transmission Inoperative, Erratic
- Turn ignition on. If anti-lock warning light goes out after self-test, go to next step. If warning light does not go out, refer to appropriate BRAKE SYSTEM - ANTI-LOCK article in BRAKES SECTION.
- Turn ignition off. Partially remove instrument cluster. See appropriate INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Using an ohmmeter, check for shorts in wiring between PSOM connector C249, terminal No. 7 (Gray/Black wire) and battery/ignition or ground. Determine if circuit is shorted. See Figure .
- Using ohmmeter, check for opens in wiring between PSOM connector C249, terminal No. 7 (Gray/Black wire) and affected module. Verify terminals in PSOM wiring connector are completely seated in connector. Determine if circuit is open. If wiring is open or shorted, repair wiring between speedometer and affected module as required. If wiring is okay, go to next step.
- Using voltmeter, connect leads between PSOM connector C249, terminals No. 7 (Gray/Black wire) and 2 (Black/White wire). If voltage increases smoothly and continuously from zero to about 4.5 volts as vehicle speed increases from zero to about 30 MPH, repair wiring between speedometer and affected module. If voltage increase is erratic or jumpy, go to next step.
- Connect a voltmeter between PSOM connector C249, terminals No. 4 (Red/Pink wire) and 5 (Light Green/Black wire). If voltage increases smoothly and continuously from zero to about 3.5 volts as vehicle speed increases from zero to about 30 MPH, replace instrument cluster. See appropriate INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. If voltage increase is erratic or jumpy, repair wiring for opens or shorts.