AC Pressure Sensor

This procedure removes and replaces the AC pressure sensor on a 2005 Dodge Viper 8.3L V10, allowing proper monitoring of refrigerant system pressure for AC operation.

Warnings

Tools required

Parts

• AC pressure sensor × 1 — Mopar 5143127AA or equivalent
• O-ring seal for sensor × 1 — Use OEM specification

Fluids

• R-134a refrigerant

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn ignition off and remove key
3. Allow engine and AC system to cool completely if recently operated
4. Locate AC pressure sensor on the AC liquid line near the condenser on the passenger side of the engine bay

Procedure

1. 1

   Recover AC refrigerant
   Connect AC recovery machine to the service ports on the AC system. Follow machine manufacturer instructions to completely recover all refrigerant from the system. Record the amount recovered for recharge reference. Verify system pressure reads zero on manifold gauges before proceeding.
   ⚠️Never open AC fittings without first recovering refrigerant. System operates at 200+ psi and can cause serious injury.
2. 2

   Disconnect sensor electrical connector
   Locate the electrical connector on the AC pressure sensor. Press the locking tab on the connector and pull directly away from the sensor to disconnect. Do not pull on the wiring harness itself.
   ℹ️The connector may be stiff if never previously removed. Use gentle wiggling motion while pulling if necessary.
3. 3

   Remove AC pressure sensor
   Using an appropriate socket, unthread the AC pressure sensor from the AC liquid line fitting. Turn counterclockwise to remove. Small amounts of residual refrigerant or oil may be present; catch with a shop towel. Inspect the sensor port threads on the line for damage.
   ⚠Do not allow dirt or debris to enter the open AC line port. Cover with a clean shop towel or plug immediately after sensor removal.
4. 4

   Prepare new sensor
   Remove the new AC pressure sensor from packaging. Check that the O-ring seal is properly seated in the sensor threads. If O-ring is separate, install it onto the sensor ensuring it sits fully in the groove. Lightly lubricate the O-ring with clean refrigerant oil of the grade specified for this system (PAG oil for R-134a) to prevent damage during installation.
5. 5

   Install new AC pressure sensor
   Thread the new AC pressure sensor into the AC liquid line fitting by hand, turning clockwise. Ensure threads engage smoothly without cross-threading. Once hand-tight, use a torque wrench and socket to tighten the sensor to the factory-specified torque (verify exact value in service manual; typical AC pressure sensor torque is approximately 7 ft-lbs).
   ⚠Do not overtighten. Excessive torque can damage the sensor body or crack the AC line fitting threads.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
6. 6

   Reconnect electrical connector
   Push the electrical connector onto the new AC pressure sensor until the locking tab clicks into place. Tug gently on the connector to verify it is fully seated and locked.
7. 7

   Evacuate and recharge AC system
   Connect manifold gauge set and vacuum pump to AC service ports. Evacuate the system for a minimum of 30 minutes to remove all moisture and air. Monitor vacuum gauge for 10 minutes after pump shutoff to verify system holds vacuum with no leaks. Recharge system with R-134a refrigerant to the factory-specified charge weight for the 2005 Viper AC system.
   ℹ️Proper evacuation is critical to prevent moisture contamination which can damage AC components and reduce cooling performance.

Reassembly

1. No disassembly was required beyond sensor removal; all components have been reinstalled during the procedure

Verification

• Start engine and turn AC system to maximum cold and maximum fan speed
• Allow system to run for 5 minutes and verify cold air is produced from vents
• With engine running and AC on, check manifold gauges to verify low-side pressure is 25-45 psi and high-side pressure is 200-250 psi at ambient temperature of 75-85°F
• Inspect sensor area and all AC line fittings for signs of refrigerant leaks (oil residue, frost formation)
• Verify AC compressor cycles on and off normally as controlled by the pressure sensor

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