Four Seasons 36678 HVAC Cut-Off Switch

Four Seasons 36678 HVAC Cut-Off Switch

Four Seasons 36678 is a system-mounted HVAC cut-off switch for high-pressure A/C protection. This pressure switch uses a 12-volt, 2-terminal pin connection with a female connector and 10mm x 1.25 female fitting for direct service replacement on the listed Cadillac applications.

Key Features

• High cut-out pressure switch for HVAC system pressure control
• System-mounted design with 10mm x 1.25 female fitting
• 12V electrical specification with 2-pin terminal layout
• Closed-comp operation
• Plastic and metal construction
• Weather Pack connection for sealed electrical performance
• Meets or exceeds OEM requirements

Product Details

The Four Seasons Pressure Switch line focuses on HVAC pressure control components used to monitor refrigerant system pressure and interrupt compressor operation at the specified threshold. Part number 36678 is a high cut-out switch with an off pressure of 420 psi and an on pressure of 225 psi, making it a direct-fit service part for pressure-based A/C system protection. This Four Seasons 36678 pressure switch is listed for 1994-2002 Cadillac Eldorado, 1994-2000 Cadillac DeVille, and 1994-1997 Cadillac Seville.

This part cross-references UAC SW11159C for the same application.

What It Helps Address

• A/C compressor cycling caused by incorrect high-side pressure readings
• HVAC shutdown triggered by a failed pressure switch
• Loss of compressor protection in high-pressure conditions
• Intermittent electrical connection at the pressure switch circuit
• Service replacement needs on Cadillac Eldorado, DeVille, and Seville HVAC systems

Installation Notes and Tips

Verify the connector style, thread size, and pressure specification before installation. This switch is system mounted and uses a female connector with pin terminals, so the existing harness and fitting must match the listed configuration. Confirm the vehicle’s A/C system pressure diagnosis before replacing the switch, and inspect the connector seal and surrounding refrigerant components during service.

Quality Assurance

Four Seasons states that this pressure switch meets or exceeds OEM requirements. The part is built with plastic and metal materials and uses a Weather Pack connection for sealed electrical performance.