Power Steering Pressure Switch: Description and Operation

Power Steering Pressure Switch:

NOTE Because different models and engine applications vary in wire colors, circuit numbers, and pin numbers, the above image is a typical example. Refer to COMPUTERS AND CONTROL SYSTEMS/SCHEMATIC AND ROUTING DIAGRAMS for specific schematic applications.

PURPOSE
Provides information to the PCM of increased load produced by the power steering system.

OPERATION
Turning the steering wheel increases power steering oil pressure and creates a load on an idling engine. The pressure switch will close before the load can cause an idling problem.

Closing the switch causes the circuit to read less than 1 volt. The PCM will increase the idle speed, retard the timing and disengage the A/C on manual transmission vehicle only. On 1994 automatic S series vehicles the switch will not be installed and the wiring will be physically on the vehicle but will be inoperative.