1990 Cadillac Seville STS Repair and Maintenance
A guide to problems, costs, maintenance and repair for your 1990 Cadillac Seville STS
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1990 Cadillac Seville STS ProblemsHeating and AC Temperature and Air Delivery Mode Door Actuators May Fail
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.
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.
The high-pressure power steering lines are known to leak.