DUAL-PRESSURE SWITCH 1. With engine off, disconnect pressure switch connector (located on receiver-drier). Connect a jumper wire across high/low pressure side of harness connector. See Fig. 4 . Install manifold gauge set to high pressure side service valve of refrigerant line. 2. Start engine and adjust engine speed to 1000 RPM with A/C clutch engaged. Turn blower switch on. Engine should be warm and doors and windows closed. 3. Check for continuity at pressure switch terminals with manifold gauges at specified pressure. See PRESSURE SWITCH SPECIFICATIONS table. Condition is normal if there is continuity between the terminals. If there is no continuity, replace switch.