Four Seasons 36573 A/C Trinary Switch

Overview of Four Seasons Pressure Switch 36573

The Four Seasons Pressure Switch 36573 is a system-mounted trinary pressure switch designed for precise HVAC control in select BMW models. Engineered to operate at specific pressure thresholds, this 12-volt switch ensures reliable performance in your vehicle's A/C clutch and compressor system.

• 12-volt electrical system compatibility
• Rectangular female connector with pin terminals
• Steel construction for durability
• Operates at multiple pressure points: low, medium, and high
• Compatible with BMW 318i, 318is, 318ti, 325i, 325is, 840Ci, 850Ci, 850CSi, 850i, and M3 models
• Meets or exceeds OEM specifications
• Weather Pack connector for secure, weather-resistant connection
• Fitting thread size 7/16" x 20 with female fitting gender
• Includes one item (part number 24650) for installation

Four Seasons Pressure Switch Product Line Details

The Four Seasons Pressure Switch product line focuses on delivering reliable pressure sensing components for automotive HVAC systems. The Pressure Switch 36573 is part of this line, providing a trinary switch solution that monitors system pressure at multiple points to control the compressor clutch and cooling fan operation effectively. This ensures proper system function and protection against abnormal pressure conditions.

Technical Description and Specifications

This A/C trinary switch operates within defined pressure ranges to maintain optimal HVAC system performance. It features four terminals with a pin-type connection housed in a gray rectangular female connector. The switch opens and closes circuits based on pressure thresholds: low pressure on at 30 psi and off at 28 psi, medium pressure on at 240 psi and off at 200 psi, and high pressure on at 350 psi and off at 455 psi. The steel body and weather-resistant Weather Pack connector provide durability and protection against environmental factors. The fitting thread size of 7/16" x 20 and female fitting gender allow for secure mounting in the system.

Applications and Common Issues Addressed

• Prevents compressor damage by monitoring high and low pressure limits
• Controls A/C clutch engagement for efficient cooling
• Regulates cooling fan operation based on system pressure
• Helps avoid system shutdowns due to pressure irregularities
• Ensures consistent HVAC performance in BMW 3 Series and 8 Series models

Installation Notes and Tips

When installing the Four Seasons Pressure Switch 36573, ensure the system is depressurized and the vehicle’s electrical system is off. Verify compatibility with your BMW model, specifically 318i, 318is, 318ti, 325i, 325is, 840Ci, 850Ci, 850CSi, 850i, or M3. Use the correct fitting thread size (7/16" x 20) and confirm the female fitting gender matches the system port. Connect the rectangular female Weather Pack connector securely to avoid moisture intrusion. Follow OEM torque specifications to prevent damage during installation.

Quality Assurance and Warranty

The Four Seasons Pressure Switch 36573 meets or exceeds OEM standards for fit, form, and function. Manufactured with steel materials and designed for durability, this switch is built to withstand typical automotive operating conditions. While specific warranty details are not provided here, Four Seasons products generally come with a limited warranty covering defects in material and workmanship. Consult product documentation or your supplier for exact warranty terms.