Checking Coolant Fan 2 -V177- (Right)

Checking coolant fan 2 -V177- (right)

Test requirements:

^ Fuse S1 04 for radiator fan OK (in 8-position relay carrier, position 22)
^ Fuse S146 for radiator fan OK (in 8-position relay carrier, position 21)

- Take connector -2- out of holder and disconnect.

- Connect multimeter for voltage measurement as follows.
^ Specification: approximately battery voltage
If readings do not match specifications:
- Use wiring diagram to eliminate open circuit in wiring.
If readings match specifications:

- Connect multimeter for voltage measurement as follows.
^ Specification: approximately battery voltage
If reading does not match specification:
- Use wiring diagram to eliminate open circuit in wiring.
If reading matches specification:

- Connect multimeter for voltage measurement between contacts 2 and 3 of connector.
^ Vehicle diagnostic, testing and information system VAS 5051 connected; vehicle self-diagnosis and vehicle system "01- Engine electronics" selected. Ignition must be on.

Indicated on VAS 5051:
- From list -1- select diagnostic function "03- Final control diagnosis".
- Keep touching 001, until the radiator exhaust control 1 is activated.
^ Voltage value must slowly drop from approximately battery voltage to roughly 8 V (and then increase again)
- Terminate function "03- Final control diagnosis" by touching 4 key.
- Switch ignition off.
If the specified value is not reached:

- Connect up test box VAG 1598/31 to wiring harness connectors. Engine control unit is not to be connected. Connect ground clip of test box to ground (not shown in Fig.).

CAUTION: So as not to destroy electronic components, select required measuring range before connecting test leads and observe test conditions.

- Check for open circuit and short to ground/positive in the following wiring.
- Use wiring diagram to eliminate open circuit in wiring/short circuit.
If no fault is found:
- Replace coolant fan 2 -V1 77- with coolant fan control (FC) control module 2 -J671.