Best A/C Thermostat Wiring Diagram A/C-HEATER SYSTEM - MANUAL :: 1993 :: Jeep Cherokee (XJ) :: Jeep - The mode control lever (upper lever) operates a vacuum activate the back of the manage panel. The vacuum switch controls vacuum to defroster, ground, panel and fresh/recirculated air vacuum cars, as well as a vacuum-actuated heater control valve (water valve) . The heater manage valve closes while vacuum is carried out to it. Make certain airflow is correct. If airflow is not correct, test for proper operation of air distribution doors and for obstructions in vent channels. If airflow is accurate, ensure compressor grab is running and pressure belt is tightened to specification. Go to step 4). (indicating evaporator temperature is too low) , or if the low stress switch contacts are open (indicating refrigerant system strain is just too low), the eu will not energize the a/c snatch relay. A/c thermostat (temperature manage thermostat) is in evaporator housing. Low stress switch is on receiver-drier. System makes use of a three-speed blower motor in preference to a blower resistor.
Ecu monitors evaporator temperature based upon the voltage reference it receives from the a/c sensor (evaporator thermistor) inside the evaporator housing. Eu video display units refrigerant stress thru low strain turn on receiver-drier. If refrigerant strain is less than 28 psi (2.0 kg/cm), the low pressure switch contacts open. Eu then stops compressor operation to save you negative the compressor. The vacuum transfer permits or denies vacuum to the fresh air door vacuum motor. The temperature control lever (decrease lever) movements a cable that controls the location of the blend-air door in the heater case . Take a look at blower motor operation. If blower motor operates, go to subsequent step. If blower motor does now not perform, take a look at fuse. If fuse is blown, update fuse. If fuse is okay, observe battery voltage directly to blower motor. If blower motor does not operate, update blower motor. If blower motor operates, replace blower transfer or repair wire harness .
The a/c transfer is closed while the lever is in any of the a/c modes (max, norm or bi-level) . The temperature manage lever (decrease lever) moves a cable that controls the location of the combo-air door in the heater case.