71R7500 Trinary Pressure Switch – 12/24V, 1/4 in. Male, 4 Terminal

Description

The Red Dot 71R7500, is a three-function pressure control switch designed for mobile air conditioning systems equipped with radiator shutters and/or electric or air fan clutches. Trinary switches are used when both compressor protection and head-pressure management are required.

This switch performs three critical functions:

1. Low-pressure protection – Prevents compressor operation if refrigerant charge is lost or ambient temperature drops too low.

2. High-pressure protection – Shuts the compressor off if discharge pressure rises too high, then automatically resets once pressure returns to normal.

3. Fan / shutter override – Activates fan or shutter control to maintain proper head pressure during high-load conditions.

The 71R7500 features a 1/4 in. male threaded fitting, 4 electrical terminals, and supports 12V and 24V systems, making it a common solution across heavy-duty, on-highway, and vocational HVAC applications.

Use the specifications and interchange numbers below to confirm proper fitment before ordering.

Product Specifications

• Part Type: Trinary Pressure Switch

• Aftermarket Part No.: 71R7500

• MEI / AirSource Part No.: 1550

• OEM Reference: RD5-4585-0

• Manufacturer: Red Dot

• Voltage: 12/24V

• Terminals: 4

• Switch Type: Normally Open

• Thread Size: 1/4 in. Male

• Refrigerant Compatibility: R12 / R134a

Pressure Settings:

• Open: 22–325 PSI

• Close: 40–230 PSI

• Application: Mobile A/C systems with fan clutches or radiator shutters

OEM & Interchange Numbers

OEM Numbers:

• Mack: 1MR2380, 1MR3439, 4379-RD535950, 4379-RD545850, 6152DA1725

• Navistar: 1691699C91

• Western Star: 02-2750417, 61522-3402

• Volvo: 61522-3801

• Ford New Holland: 620205

Aftermarket / Interchange:

• Alliance: ABP N83 318009, ABP N83 318039

• Bergstrom: 650449, 650634

• Climatech: BC1005, BC10050

• Four Seasons: 35899

• Kysor: 2299004 (404171 old)

• Murray: 207076, 207093

• Motivaire: 1-1018

• Omega: 29-30734

• Primatech: PTAC1550

• Texas Truck AC: 850-8950

• Truck Air / MEI: 11-2625, 44890

• Red Dot Factory: RD-5-17605-0P, RD-5-4585-0P

• Red Dot Aftermarket: 71R7500

• Additional references: 03-13035, 232-8544, 923-1106, SWI3406, VE2066