This procedure covers replacement of the AC high pressure switch (also called the high pressure cut-off switch) located on the AC line near the condenser on 2015-2020 Ford F-150 trucks with the 5.0L V8 Coyote engine.

Warnings

Tools required

Parts

• AC high pressure switch × 1 — Use OEM specification or Motorcraft SW-7430
• AC line O-rings × 2 — Use OEM specification
• R-134a refrigerant × 1 — Typically 1.5-2.0 lbs
• PAG 46 oil × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn off engine and allow to cool completely if recently operated
3. Open hood and secure with prop rod
4. Wear safety glasses and gloves throughout this procedure
5. Verify AC system has not been recently operated (lines should be cool to touch)

Procedure

1. 1

   Recover AC refrigerant
   Connect AC recovery machine to service ports (low side on accumulator, high side near condenser). Follow recovery machine instructions to fully evacuate all refrigerant from the system. Verify recovery is complete when machine indicates zero pressure and no additional refrigerant is being captured. Record amount of refrigerant and oil recovered for recharge reference.
2. 2

   Locate high pressure switch
   The high pressure switch is mounted on the high pressure AC line between the condenser and compressor, typically on the passenger side near the radiator support. It is a small cylindrical sensor with a single electrical connector. On the 5.0L V8 F-150, it is usually accessible from above without removing other components.
3. 3

   Disconnect electrical connector
   Press the connector release tab and pull the electrical connector straight off the high pressure switch. Do not pull on the wiring harness itself. Inspect connector terminals for corrosion or damage.
4. 4

   Remove high pressure switch
   Using appropriate wrench or socket, turn the high pressure switch counterclockwise to unthread it from the AC line port. The switch typically has a 1 inch or 24mm hex body. Remove switch completely and inspect the sealing O-ring for damage. Some residual oil may drip from the port.
5. 5

   Inspect AC line port
   Examine the threaded port on the AC line for damage, debris, or metal shavings. Clean threads with lint-free cloth if needed. Check for any signs of leakage or corrosion around the port area. Replace AC line if threads are damaged or cross-threaded.
6. 6

   Prepare new high pressure switch
   Remove new high pressure switch from packaging. Verify it matches the old switch design and thread size. Install new O-ring onto the switch if not pre-installed. Lightly coat O-ring with clean PAG 46 oil (typically 1-2 drops) to aid installation and ensure proper seal.
7. 7

   Install new high pressure switch
   Thread new high pressure switch into AC line port by hand, turning clockwise. Ensure switch threads in smoothly without resistance. Tighten switch to manufacturer specification using torque wrench. Do not over-tighten as this can damage the port threads or crack the switch body. Final position should allow electrical connector to attach without strain on wiring.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
8. 8

   Reconnect electrical connector
   Push electrical connector onto new high pressure switch until it clicks securely into place. Tug gently on connector to verify it is fully seated and locked. Ensure wiring harness has adequate slack and is not routed near sharp edges or hot components.
9. 9

   Evacuate AC system
   Connect vacuum pump to AC service ports using manifold gauges. Run vacuum pump for minimum 30-45 minutes to remove all air and moisture from the system. System should achieve and hold at least 28-29 inches of mercury vacuum. After evacuation period, close manifold valves and observe vacuum gauge for 10 minutes - vacuum should not rise more than 2 inches indicating no leaks.
10. 10

    Recharge AC system
    With system under vacuum, connect refrigerant supply to manifold gauges. Add the amount of R-134a recovered in Step 1, or refer to underhood AC specification label (typically 1.75-2.0 lbs for F-150). Charge through low side port only with engine running at 1500 RPM and AC on MAX/recirculate. Monitor system pressures - low side should be 25-45 PSI, high side 200-250 PSI at ambient temperature. Add PAG oil if total recovered was less than expected (typically 1-2 oz).
11. 11

    Leak test system
    With system charged and pressurized, use electronic leak detector to check for leaks at the high pressure switch installation point and all other AC line connections. Pay special attention to the switch threads and O-ring seal. If leak is detected, recover refrigerant and verify proper installation and torque of switch.

Reassembly

1. Verify all electrical connections are secure and properly routed
2. Ensure no tools or parts were left in engine compartment
3. Check that high pressure switch mounting location is free of interference with other components

Verification

• Start engine and turn AC to MAX cool with fan on high speed
• Verify AC compressor engages and cycles normally
• Check that cold air is produced at vents within 2-3 minutes
• Monitor AC pressures with gauges - low side 25-45 PSI, high side 200-250 PSI at idle
• Verify high pressure switch connector is secure and shows no warning lights on dash
• Perform final leak check around switch location with engine running and AC operating
• Test AC performance during short test drive - system should maintain cold air output
• Verify high pressure switch cuts off compressor if system reaches excessive pressure (safety function)

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