A/C High Pressure Switch
WARNING: This page is about a different car, the 2002 GMC Safari and 2002 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.
The A/C system is protected by two pressure switches. The A/C high pressure switch is a two wire normally open switch. The A/C high pressure switch opens the A/C request signal when the A/C line pressure exceeds 450-490 psi (31.7-35.0 kg/cm2 ). This prevents the A/C compressor from operating.