Refrigerant Control Solenoid Valve: Description and Operation

Circuit Operation, Rear A/C Refrigerant Control Valve
When front A/C has been selected and the Compressor Clutch (K107) is engaged, the [1][2]Compressor Clutch Relay (K108) is energized and voltage is applied on the BG wires to the Rear A/C Refrigerant Control Valve (K207). When rear A/C is selected a ground signal is applied to the Rear A/C Switch Amplifier (Z216). The Rear A/C Switch Amplifier (Z216) then applies a ground signal to energise the Rear A/C Control Relay (K194) and the Rear A/C Fan Speed Relay (K205). When the Passenger's Rear Fan Speed Switch (X246) is in any position other than Off, ground is applied to the Rear A/C Refrigerant Control Valve (K207) through the closed contacts of the Passenger's Rear Fan Speed Switch (X246), BR wire, closed contacts of the Rear A/C Fan Speed Relay (K205), PG wire, UB wire, Rear A/C Refrigerant Control Valve Diode (Z228), P wire, closed contacts of the Rear A/C Evaporator Temperature Switch (X260), and the RG wire.

The Rear A/C Evaporator Temperature Switch (X260) senses the temperature of the exterior fins. Should ice begin to form due to low temperature, the switch will open and the ground supply to the Rear A/C Refrigerant Control Valve (K207) will then be interrupted. The valve de-energizes and refrigerant flow is interrupted.

The Rear A/C Refrigerant Control Valve (K207) will also be de-energized if one or more of the following conditions occurs:
1. The Front A/C Switch (X225) has been turned OFF.
2. The Front Fan Speed Switch (X247) has been turned OFF.
3. The Rear A/C switches have been turned OFF.
4. The Passenger's Rear Fan Speed Switch (X246) has been turned OFF.
5. The ECM determines that compressor clutch operation is no longer required.
6. Compressor Clutch (K107) operation has been disabled by the A/C Dual Pressure Switch (X102) or the Front A/C Evaporator Temperature Switch (X101).
7. Compressor Clutch (K107) operation has been disabled by the Compressor Clutch Cut-Out Switch (X259) (300Tdi Without EDC Only).