Four Seasons 20963 A/C Trinary Switch

Four Seasons 20963 Trinary Pressure Switch

Four Seasons 20963 is a system-mounted A/C trinary pressure switch for 12-volt HVAC systems. It monitors refrigerant pressure and helps control compressor and fan operation in the A/C clutch and compressor circuit, making it a direct-fit service part for select Audi and Volkswagen applications.

Built with a steel body, oval female connector, pin terminals, and Weather Pack sealing, this Four Seasons Pressure Switch is made to meet or exceed OEM requirements. The M10 x 1.25 female fitting and 4-terminal layout support accurate electrical and pressure control in factory-style air conditioning systems.

Key Features

• Four Seasons Pressure Switch line, part number 20963
• System-mounted trinary pressure switch for HVAC A/C clutch and compressor control
• 12-volt electrical design with 4 terminals
• Oval female connector with pin terminals and Weather Pack sealing
• Steel construction with female M10 x 1.25 fitting
• Meets or exceeds OEM specifications
• Pressure operating points: low on 25 psi, low off 22 psi, medium on 240 psi, medium off 195 psi, high on 260 psi, high off 440 psi

Detailed Description

This Four Seasons 20963 trinary pressure switch is used in system-mounted automotive A/C circuits to monitor refrigerant pressure and manage compressor engagement and condenser fan operation. It is a practical replacement for Audi A4, Audi A6, Audi A8 Quattro, Audi S4, Audi S6, Audi S8, Audi Allroad Quattro, and Volkswagen Passat models that use this style of pressure switch. The part number 20963 is also cross-referenced with UAC SW11150C for the same application.

Compatible With 1996-2002 Audi A4, N/A; 1996-2002 Audi A4 Quattro, N/A; 1996-2004 Audi A6, N/A; 1996-2004 Audi A6 Quattro, N/A; 1997-2000 Audi A8, N/A; 1997-2003 Audi A8 Quattro, N/A; 1998-2005 Volkswagen Passat, N/A; 2001-2005 Audi Allroad Quattro, N/A; 2001-2002 Audi S4, N/A; 2001-2003 Audi S3, N/A; 2001-2003 Audi S6, N/A; 2001-2003 Audi S8, N/A.

What It Helps Solve

• A/C compressor cycling caused by faulty pressure switch readings
• Condenser fan control issues tied to refrigerant pressure signals
• Intermittent air conditioning operation in Audi and Volkswagen HVAC systems
• Pressure-related compressor cutout or failure to engage
• Electrical connection problems at the A/C pressure switch interface

Installation Notes and Tips

Verify the connector shape, terminal count, and M10 x 1.25 fitting before installation. This system-mounted switch is intended for vehicles that use a trinary pressure switch in the A/C circuit, so confirm the original part number and pressure thresholds match the vehicle’s HVAC specification. For best results, inspect the connector and surrounding wiring for corrosion or heat damage during replacement.

Quality Assurance

Four Seasons designs this Pressure Switch to meet or exceed OEM requirements for fit and function. The 20963 part number is built for factory-style service replacement in select Audi and Volkswagen air conditioning systems.