Vehicles after change point in 1982 CHECKING HEATING AND EVAPORATOR TEMPERATURE REGULATION Heating and Evaporator Temperature Regulation Principle Wiring Diagramm: 1 Heating regulator (control unit) 2 Inside temperature sensor 3 Water valve 4 Heater temperature sensor 5 Heater blower 6 Evaporator blower 7 A/C compressor clutch 8 Evaporator temperature sensor 9 Air conditioner switch 10 Evaporator temperature regulator 11 Low pressure pressostat 12 Temperature switch 110° C (230° F) + 15 E = Power saving relay + 15 S = Power fuse - 31 = Ground |  |
The inside temperature of the car can be adjusted with the heating regultaion control knob (1). Control knob turned to left final stop = cold, no heating. Control knob turned to right final stop = warm, maximum heating. A so-called "control range" is between botch end positions of the heating regulator (control unit). A temperature (nominal value) set in this range will be regulated by the control unit. The temperature inside of the car and the heater blowing out temperature are measured with one each temperature sensor and compared with the given nominal value in the control unit. A valve in the feed of the hot water circuit will be opened more or less long depending on the amount of deviation from the nominal value and the temperature inside of the car is regulated in this manner. The water valve is operated electromagnetically. The electric control of the water valve is designed that the water valve will be opened and therefore maximum heating will be provided, if the electrical system would fail (e.g. faulty control unit). In case of malfunctioning and/or failure of the heating regulation system, defects must be found in the system with the following test plan. The heating and evaporator temperature regulation corresponds with the previously described heating regulation when the air conditioner is switched off. Heating regulation and the heater blower do not work when the air conditioner is switched on. The A/C compressor clutch is activated by the evaporator temperature regulator, which works in accordance with the evaporator temperature sensor and heating regulator (control unit). |  |
