Chrysler Full-Size Trucks 1989-1996 Repair Guide

Expansion Valve


For 1989-93 models an H-type expansion valve is used to meter refrigerant onto the evaporator in accordance with cooling requirements. A low-pressure cut-off switch is mounted on the expansion valve assembly. The cut-off switch is wired in series with the compressor clutch. The switch cuts off the power supply to the clutch when refrigerant pressure drops off below a given point.


See Figure 1

  1. Discharge the refrigerant system. Refer to Routine Maintenance for the proper safe procedure.
  3. Disconnect the negative battery cable. Disconnect the wires from the low pressure cut-off switch.

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Fig. Fig. 1: Exploded view of the expansion valve

  1. Remove the center refrigerant line assembly mounting plate screw. Carefully pull the mount and lines toward the front of the truck, away from the H-valve.
  3. Remove the valve mounting screws, while holding the valve so that it will not fall. Remove the valve.
  5. Clean the mounting surface on the line mounting assembly and evaporator.
  7. Install new mounting gaskets, at the evaporator and line mount.
  9. Remove the sealing cap from the evaporator side of the new expansion valve. Install the H-valve to the evaporator. Tighten the mounting screws to 30 inch lbs. (11 Nm).
  11. Remove the sealing cap from the line side of the H-valve. Mount the line assembly to the H-valve. Tighten the screws to 200 inch lbs. (23 Nm).
  13. Connect the low pressure cut-off switch and the negative battery cable. Evacuate, charge and leak test the system.