AC High Pressure Switch

This procedure covers the replacement of the AC high pressure switch on a 2018-2024 Honda Accord with 1.5L turbocharged engine, including refrigerant recovery and system recharge.

Warnings

Tools required

Parts

• AC high pressure switch × 1 — Use OEM Honda specification
• O-rings for AC line fittings × 2 — Use OEM Honda specification

Fluids

• R-1234yf refrigerant
• PAG oil (ND-12)

Preparation

1. Ensure engine is cool to the touch
2. Park vehicle on level surface and engage parking brake
3. Turn ignition to OFF position and remove key
4. Connect AC recovery machine and fully recover refrigerant from system according to machine instructions
5. Record the amount of refrigerant and oil recovered for proper recharge quantities
6. Open hood and secure in upright position

Procedure

1. 1

   Locate the AC high pressure switch
   The high pressure switch is located on the AC high pressure line near the condenser on the driver side of the engine bay, forward of the battery. It has a single electrical connector and threads directly into the AC line.
2. 2

   Disconnect the electrical connector
   Press the locking tab on the electrical connector and pull straight out to disconnect from the high pressure switch. Move the wiring harness aside to provide working clearance.
3. 3

   Remove the high pressure switch
   Using a 10mm socket or appropriate wrench, carefully unthread the high pressure switch counterclockwise from the AC line fitting. Remove the switch completely and inspect the threads in the AC line for damage or debris.
4. 4

   Inspect and clean the mounting port
   Examine the threaded port in the AC line for any contamination, metal shavings, or cross-threading damage. Use a clean lint-free cloth to wipe the area clean. Remove and discard the old O-ring from the port.
5. 5

   Prepare the new high pressure switch
   Install a new O-ring onto the new high pressure switch. Apply a thin coat of fresh ND-12 PAG oil to the O-ring and threads. Do not over-lubricate as excess oil will contaminate the system.
6. 6

   Install the new high pressure switch
   Thread the new high pressure switch by hand clockwise into the AC line port until it seats against the O-ring. Ensure it threads smoothly without resistance. Tighten to the specified torque using a torque wrench.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
7. 7

   Reconnect the electrical connector
   Plug the electrical connector onto the new high pressure switch until you hear and feel a positive click, confirming the locking tab is engaged. Gently tug on the connector to verify it is secured.
8. 8

   Evacuate the AC system
   Connect the AC service machine and evacuate the system for a minimum of 30 minutes to remove all air and moisture. Monitor the vacuum gauge to ensure the system holds vacuum, indicating no leaks at the switch installation.
9. 9

   Recharge the AC system
   Using the AC service machine, recharge the system with the correct amount of R-1234yf refrigerant as recorded during recovery (typically 400-450 grams total system capacity). Add the appropriate amount of ND-12 PAG oil to compensate for any oil lost during the repair.

Reassembly

1. No additional reassembly required for this procedure

Verification

• Start the engine and allow it to idle
• Turn AC to maximum cooling with fan on high speed
• Verify AC compressor engages and cycles normally
• Check for cold air from vents (vent temperature should be 40-50°F at idle)
• Inspect the high pressure switch connection for any signs of refrigerant leakage using leak detector if available
• Verify no warning lights on instrument cluster related to AC system
• Monitor AC system pressures using service machine gauges (high side should be 200-250 psi at idle with ambient temperature 70-80°F)
• Confirm electrical connector is fully seated and locked

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