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Test step 8: > < Checking the cut-in signal for the air conditioner compressor regulating valve N280

A2

Test step 7:
Test step 7:
Actuation of the radiator fan -V7- (speeds 1 and 2)
   
Vehicle diagnostic, testing and information system -VAS 5051-, measurement mode: Multimeter, current measurement (10 A =)
l  Adapter -V.A.G 1598/12- connected
Test stepTest box -V.A.G 1598 A- socketBeing tested:
l  Test conditions
–  Additional operations
SpecificationRemedies if the specification is not attained
7.18
+
14		Actuation of speed 1 for the radiator fan -V7-
l  The engine is running
–  The fan does not start running until the test lead has been connected
t  Greater than 0.1 A and less than 1.0 A
–  Using the current flow diagram, locate and rectify a short circuit to earth in the wiring between the operating and display unit for air conditioner/Climatronic -E87- and the control unit for the radiator fans -J293-
    
t  Fan running at speed 1
–  Using the current flow diagram, locate and rectify an open circuit in the wiring between the operating and display unit for air conditioner/Climatronic -E87- and the control unit for the radiator fans -J293-
–  Check the actuation of the radiator fan -V7-. → Electrical System; Repair group 01
7.29
+
14		Actuation of speed 2 for the radiator fan -V7-
l  The engine is running
–  The fan does not start running until the test lead has been connected
t  Greater than 0.1 A and less than 1.0 A
–  Using the current flow diagram, locate and rectify a short circuit to earth in the wiring between the operating and display unit for air conditioner/Climatronic -E87- and the control unit for the radiator fans -J293-
    
t  Fan running at speed 2
–  Using the current flow diagram, locate and rectify an open circuit in the wiring between the operating and display unit for air conditioner/Climatronic -E87- and the control unit for the radiator fans -J293-
–  Check actuation of the radiator fan -V7-. → Electrical System; Repair group 01

  Note
t  The operating and display unit for air conditioner/Climatronic -E87- switches a signal to the control unit for the radiator fans -J293- as soon as the compressor is switched on (speed 1) and, when the compressor is switched on, as soon as the pressure in the coolant circuit exceeds a specified value (speeds 1 and 2) → Chapter (measured value block in display group “001”.) The control unit for the radiator fans -J293- switches on the radiator fan -V7-.
t  Actuation of the radiator fan -V7- by the control unit for the radiator fans -J293- only occurs when the engine is running (voltage at terminal “61”).
t  The control unit for radiator fan -J293- switches the radiator fan -V7- to speed 1 when the thermostatic switch for the radiator fan -F54- is closed (between contacts “1” and “2” it closes at approx. 95 °C) and to speed 2 when the thermostatic switch for the radiator fan -F18- is closed (between contacts “3” and “2” it closes at approx. 102 °C) → ”Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations”, → Relevant Workshop Manual, Injection and Ignition System; Repair group 01 and → Relevant Workshop Manual, Diesel Direct Injection and Glow Plug System; Repair group 01
   

Test step 8: > < Checking the cut-in signal for the air conditioner compressor regulating valve N280