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→ Pin assignment for air conditioner pressure switch -F129
Switch between contact 1 and 2 (opens in the event of vacuum and overpressure in the refrigerant circuit - the compressor is switched off)
Switch between contacts 3 and 4 (closes if pressure increases in the refrigerant circuit - the radiator fan is switched to 2nd speed)
Pin assignment at refrigerant temperature switch -F18 / -F54
Switch -F54 (between contact 1 and 2 closes at approx. 95 °C - the radiator fans are switched to 1st speed).
Switch -F18 (between contact 3 and 2 closes at approx. 102 °C - the radiator fans are switched to 2nd speed).
Refrigerant temperature control switch (too hot) -F14
Switch opens at approx. 118 °C - the compressor is switched off.
Note:
Only installed in vehicles with pressure switch -F129
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
Test step 1 (voltage supply)
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Select measuring range on hand-held multimeter V.A.G 1526:
Voltage measurement (20V =)
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Test step
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Contact at connector to -J293
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Testing of
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▪ Test conditions
- Additional operations
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Specified value
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Remedies if specified value not attained
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1.1
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Connector B contact 3
and
connector A, contact 6
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Voltage supply
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- approx. battery voltage
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- Use current flow diagram to repair power supply and/or earth connection.
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1.2
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Connector B contact 4
and
connector A, contact 6
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Voltage supply
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- approx. battery voltage
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- Use current flow diagram to repair power supply.
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Select measuring range on hand-held multimeter V.A.G 1526:
Voltage measurement (20V =)
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Test step
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Contact at connector to -J293
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Testing of
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▪ Test conditions
- Additional operations
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Specified value
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Remedies if specified value not attained
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1.3
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Connector A contact 4
and
connector A, contact 6
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Voltage supply
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- approx. battery voltage
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- Use current flow diagram to repair power supply.
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1.4
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Connector A contact 9
and
connector A, contact 6
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Voltage supply
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▪ Ignition on.
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- approx. battery voltage
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- Use current flow diagram to repair power supply.
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Test step 2 (actuation of radiator fan)
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Select measuring range on hand-held multimeter V.A.G 1526:
Voltage measurement (20V =)
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Test step
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Contact at connector to -J293
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Testing of
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▪ Test conditions
- Additional operations
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Specified value
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Remedies if specified value not attained
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2.1
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Connector A contact 5
and
connector A, contact 6
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"Fan ON" signal from -E87 (1st speed from -E87).
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▪ Engine running
Operating and display unit -E87 in "auto" mode (compressor on)
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- approx. battery voltage
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- Use circuit flow diagram to locate and rectify open circuit or short circuit to earth in the wiring between control unit
-J293 and -E87.
Renew operating and display unit -E87.
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Select measuring range on hand-held multimeter V.A.G 1526:
Voltage measurement (20V =)
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Test step
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Contact at connector to -J293
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Testing of
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▪ Test conditions
- Additional operations
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Specified value
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Remedies if specified value not attained
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2.2
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Connector A contact 2
and
connector A, contact 6
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"Fan ON" signal from -E87 (2nd speed from pressure switch -F129).
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▪ Connector removed from pressure switch -F129, and contacts 3 and 4 jumpered
▪ Ignition on.
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- approx. battery voltage
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- Use current flow diagram to rectify voltage supply to pressure switch -F129.
Use current flow diagram to locate and eliminate open circuit in the wiring between pressure switch -F129 and control unit -J293.
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Select measuring range on hand-held multimeter V.A.G 1526:
Voltage measurement (20V =)
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Test step
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Contact at connector to -J293
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Testing of
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▪ Test conditions
- Additional operations
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Specified value
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Remedies if specified value not attained
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2.3
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Connector A
and
connector B attached to -J293
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Actuation of fan -V7 (speed 2) from pressure switch -F129.
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▪ Ignition on.
▪ Connector detached from pressure switch -F129.
Contacts 3 and 4 jumpered (at connector to -F129).
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- Radiator fan running at speed 2
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- Use current flow diagram to rectify voltage supply to pressure switch -F129.
Use current flow diagram to locate and eliminate open circuit in the wiring between control unit -J293 and fans -V7.
Service radiator fan -V7.
Control unit -J293 defective - replace.
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Select measuring range on hand-held multimeter V.A.G 1526:
Voltage measurement (20V =)
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Test step
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Contact at connector to -J293
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Testing of
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▪ Test conditions
- Additional operations
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Specified value
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Remedies if specified value not attained
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2.4
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Connector B contact 2
and
connector A, contact 6
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"Fan ON" signal from -E87 (1st speed from temperature switch -F54).
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▪ Connector detached from temperature switch -F18/-F54, and contacts 1 and 2 jumpered
▪ Ignition on.
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- approx. battery voltage
Radiator fan running at speed 1
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- Use current flow diagram to rectify voltage supply to temperature switch -F54.
Use current flow diagram to locate and eliminate open circuit in the wiring between temperature switch -F54 and control unit -J293.
Use current flow diagram to locate and eliminate open circuit in the wiring to fans -V7.
Service radiator fan -V7.
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Select measuring range on hand-held multimeter V.A.G 1526:
Voltage measurement (20V =)
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Test step
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Contact at connector to -J293
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Testing of
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▪ Test conditions
- Additional operations
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Specified value
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Remedies if specified value not attained
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2.5
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Connector A contact 7
and
connector A, contact 6
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"Fan ON" signal from -E87 (2nd speed from temperature switch -F18).
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▪ Connector detached from temperature switch -F18/-F54, and contacts 2 and 3 jumpered
▪ Ignition on.
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- approx. battery voltage
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- Use current flow diagram to rectify voltage supply to temperature switch -F18.
Use current flow diagram to locate and eliminate open circuit in the wiring between temperature switch -F18 and control unit -J293.
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Select measuring range on hand-held multimeter V.A.G 1526:
Voltage measurement (20V =)
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Test step
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Contact at connector to -J293
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Testing of
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▪ Test conditions
- Additional operations
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Specified value
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Remedies if specified value not attained
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2.6
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Connector A
and
connector B attached to -J293
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"Fan ON" signal from -E87 (2nd speed from temperature switch -F18).
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▪ Connector detached from temperature switch -F18/-F54, and contacts 2 and 3 jumpered
▪ Ignition on.
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- Radiator fan running at speed 2
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- Use current flow diagram to locate and eliminate open circuit in the wiring to fans -V7.
Service radiator fan -V7.
Control unit -J293 defective - replace.
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Test step 3 (actuation of magnetic clutch)
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Select measuring range on hand-held multimeter V.A.G 1526:
Voltage measurement (20V =)
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Test step
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Contact at connector to -J293
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Testing of
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▪ Test conditions
- Additional operations
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Specified value
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Remedies if specified value not attained
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3.1
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Connector A contact 8
and
connector A, contact 6
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"Compressor ON" signal from -E87
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▪ Engine running
▪ Operating and display unit -E87 in "auto" mode (compressor on)
▪ No compressor shutoff condition is displayed in the -E87 measured value block (display group 001).
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- approx. battery voltage
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- Use current flow diagram to locate and eliminate open circuit or short to positive or earth in the wiring between pressure switch -F129, temperature switch -F14 and control unit -J293.
Refrigerant temperature switch -F14 defective (open) or refrigerant too hot - check.
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
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Select measuring range on hand-held multimeter V.A.G 1526:
Current measurement (20 A=)
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Test step
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Contact at connector to -J293
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Testing of
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▪ Test conditions
- Additional operations
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Specified value
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Remedies if specified value not attained
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3.2
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Connector A contact 4
and
connector A, contact10
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Actuation of air conditioner magnetic clutch -N25
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▪ Ignition on.
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- Less than 10 A
Magnetic clutch clicks (when applying voltage)
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- Use current flow diagram to locate and eliminate open circuit or short to earth in the wiring between control unit -J293 and magnetic clutch -N25.
Open circuit in the earth connection to magnetic clutch -N25
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
Magnetic clutch defective - rectify.
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