Four Seasons 20048 A/C Trinary Switch

Four Seasons 20048 Trinary Pressure Switch

The Four Seasons Pressure Switch 20048 is a system-mounted A/C trinary switch built for 12-volt HVAC systems. It monitors refrigerant pressure and helps control compressor and fan operation in the air conditioning circuit.

Key Features

• System-mounted trinary pressure switch for A/C clutch and compressor control
• 12-volt electrical design with 4 terminals
• Oval female connector with pin terminals
• Male fitting with 3/8" x 24 thread size
• Steel construction
• Pressure operating points: low on 45 psi, low off 38 psi, medium on 240 psi, medium off 195 psi, high on 290 psi, high off 395 psi
• Meets or exceeds OEM requirements

Product Details

Four Seasons 20048 is a pressure-style trinary switch used in HVAC systems that need both compressor protection and fan control based on refrigerant pressure. The switch is mounted in the system and uses pressure thresholds to manage low, medium, and high pressure events, helping the A/C circuit respond correctly under changing operating conditions. This part cross-references Global Parts Distributors LLC (e.g., 1711486) for the same application.

Compatible with 1993-1997 Nissan Altima and 1993-1996 INFINITI G20 applications that use this style of system-mounted trinary pressure switch. For buyers searching for a Nissan Altima A/C trinary switch or INFINITI G20 pressure switch, part number 20048 is the direct reference to verify against the original component.

Common Issues This Part Can Address

• A/C compressor not engaging due to pressure switch failure
• Cooling fan control problems tied to refrigerant pressure signals
• Intermittent air conditioning operation from worn electrical contacts
• Incorrect pressure-based shutdown or cut-in behavior
• HVAC system faults related to a damaged or inaccurate trinary switch

Installation Notes

Verify connector shape, terminal count, fitting thread size, and pressure settings before installation. This Four Seasons pressure switch 20048 uses a female oval connector, pin terminals, and a 3/8" x 24 male fitting, so matching the original HVAC switch configuration is important for proper operation. Confirm system pressure is correct before replacing the switch, and inspect the surrounding A/C circuit for wiring or refrigerant-related issues if the original part failed.

Quality Assurance

Four Seasons lists this trinary pressure switch as meeting or exceeding OEM requirements. The steel-bodied design and OE-style electrical and pressure specifications support direct replacement use in the listed Nissan Altima and INFINITI G20 applications.