Power Steering Pressure Switch

Power steering pressure switch is used to signal the engine Electronic Control Module (ECM) when power steering fluid pressure rises to certain point. ECM will then raise the idle speed, and cut off the A/C compressor clutch (if equipped). Switch is located in pressure line near reservoir.
When pressure at switch reaches 469-669 psi (33-47 kg/cm² ), switch will close (continuity). Pressure switch contacts will open at 349 psi (25 kg/cm² ).
To test switch, start engine and bring to operating temperature. Keep wheels straight ahead. Ensure power steering system fluid is full and system is operating correctly. With engine idling and A/C on (if equipped), turn steering to left lock. A/C compressor clutch should cut off and idle speed should increase.
Shut off A/C. Turn steering wheel to left lock. Engine speed should increase. If system does not operate correctly, disconnect 2 wires at pressure switch.
CAUTION: DO NOT connect ohmmeter to power steering pressure switch with ECM wiring harness connected. ECM damage may occur.
With engine running at idle and steering gear turned to left lock, switch should show continuity. If not, replace switch.