Four Seasons 36581 A/C Trinary Switch

Four Seasons 36581 Trinary Pressure Switch

The Four Seasons 36581 is a system-mounted A/C trinary pressure switch built for 12-volt HVAC systems. It uses a wire lead connector, a 4-terminal layout, and an M10 x 1.25 female fitting to support pressure-based control in the air conditioning circuit.

As part of the Four Seasons Pressure Switch line, this component is made for direct system mounting and meets or exceeds OEM requirements. It is a steel-bodied trinary switch with open compressor and fan settings, making it a practical replacement for service work on Volvo 850 A/C systems.

Key Features

• Four Seasons part number 36581
• A/C trinary switch for HVAC pressure control
• 12-volt electrical design with 4 terminals
• Wire lead connector and wire lead connector gender
• System-mounted installation location
• Female fitting with M10 x 1.25 thread size
• Steel construction
• Meets or exceeds OEM specifications

Detailed Description

The Four Seasons Pressure Switch 36581 is a system-mounted trinary pressure switch used in automotive A/C systems to monitor refrigerant pressure and support compressor and fan circuit control. Its open compressor and fan settings, along with the 4-terminal wire lead design, make it a direct-fit service part for vehicles that use this style of HVAC pressure control. This part cross-references UAC SW11461C for the same application.

Compatible With 1994-1997 Volvo 850, pressure switch applications. If you are servicing a Volvo 850 A/C system and need a replacement trinary pressure switch, Four Seasons 36581 provides the correct thread size, connector style, and system-mounted configuration for the listed fitment.

What It Helps Address

• A/C compressor cycling caused by pressure switch failure
• Cooling fan control issues tied to refrigerant pressure sensing
• Intermittent HVAC operation from worn electrical contacts
• Leaks or fitment problems at the pressure switch connection point
• Incorrect pressure signal input in the A/C control circuit

Installation Notes and Tips

Verify the original switch style, connector type, and M10 x 1.25 thread before installation. Because this is a system-mounted trinary pressure switch, confirm the vehicle uses the same pressure-switch configuration and electrical terminal count. Inspect the connector lead and sealing surface during replacement to help ensure proper operation on Volvo 850 HVAC systems.

Quality Assurance

Four Seasons identifies this pressure switch as meeting or exceeding OEM requirements. The steel construction and OE-style fitment support consistent replacement quality for 1994-1997 Volvo 850 A/C service.