One or more heater & AC (HVAC) temperature and/or air delivery mode door actuator may fail, resulting in improper temperature or air delivery. If this occurs, fault code(s) should be stored in the HVAC control module which should assist in diagnoses.
Resources for the Repair and Maintenance of your 1990 Cadillac Seville STS
1990 Cadillac Seville STS
1990 Cadillac Seville STS Problems
The anti-lock brake system (ABS) control module may fail causing the ABS light to illuminate. Failed modules should be replaced to restore ABS operation.
The trunk pull down switch may fail causing the trunk lid not to close completely. Our technicians tell us that the failed switch can be replaced without changing the complete pull down motor assembly.
The parking brake may not release automatically due to a failed vacuum switch or actuator. Our technicians tell us that if vacuum is supplied to the actuator when the transmission is in gear, the vacuum switch is functioning and replacing the actuator should correct this concern.
Problems with anti-theft systems using the raised-chip key can prevent the car from starting. The wires in the steering column to the ignition lock cylinder tend to break. The key and ignition lock cylinder should be replaced to correct this condition.