Repair instructions for plausibility of the sensors

Plausibility check of the sensors

Precondition

• Provision of a thermometer with digital display.
  
• Perform the check in a suitable work bay with an ambient temperature between 20 °C (68 °F) and 30 °C (86 °F).
  

Internal temperature sensor (only IHKA)

Check the internal temperature sensor as follows.

• Close windows and doors.
  
• Use a thermometer to measure the inside temperature at the height and in the vicinity of the internal temperature sensor.
  
• Compare the measured temperature with the display of the internal temperature sensor in the test module. The values must be approximately the same.
  
• Alternately blow hot and clod air into the ventilation opening of the internal temperature sensor. The display for the internal temperature sensor in the test module must change accordingly.
  

Important!

Do not use a hot air blower to blow warm air into the ventilation opening of the internal temperature sensor.

Outside temperature sensor

Check the outdoor temperature sensor as follows.

• Measure the outside temperature with a thermometer.
  
• Compare the measured temperature with the display of the outdoor temperature sensor in the test module. The values must be approximately the same.
  

Condensation sensor (only IHKA)

Check the condensation sensor as follows.

• Hold a damp cloth for around 10 seconds at the lower end of the mirror base.
  
• Observe the display for the condensation sensor in the test module; the value must rise.
  
• Remove the cloth from the mirror base.
  
• Observe the display for the condensation sensor in the test module; the value must fall.
  

Solar sensor (only IHKA)

Check the solar sensor as follows.

• Shine a conventional torch on the solar sensor (do not use neon light).
  
• Observe the display for the solar sensor in the test module. The displayed change must change according to the light intensity.
  

Evaporator temperature sensor

Check the evaporator temperature sensor as follows.

• Set a medium blower speed.
  
• Allow the engine to warm up.
  
• Set the heater to warm for a short time.
  
• Observe the display for the evaporator temperature sensor in the test module; the value must rise.
  
• Switch off the heater and switch on the air conditioning system.
  
• Observe the display for the evaporator temperature sensor in the test module; the value must fall.
  

Note regarding the evaporator temperature sensor

If the air conditioning system is in operation for a longer period, the evaporator temperature falls to 1°C (33.8°F).

Coolant pressure sensor

Check the refrigerant pressure sensor as follows.

• Connect the service station to the refrigerant circuit.
  
• Use the service station to determine the refrigerant pressure.
  
• Compare the determined refrigerant pressure with the display of the refrigerant pressure sensor in the test module. The values must be approximately the same.