Thread: Electric fan TD6

Hello,

i have searched a lot trough various forums.
My electric fan is doing nothing when you switch on the a/c.
A/C is fully working but you notice on red light stops that the air is getting warmer.
Even with 38 grad celsius outside the fan is not working.

What i did:
- Checked fan via tester - working
- Fuses checked, seems OK
- Refrigerant pressure sensor seems to bring valuables that are ok
- Ordered a new fan, same problem, not switching on. Checked via tester - working

So i’m now very aimles. Any ideas what to do next?

Thanks!

Klemens

from the manual:
"
Cooling Fan – Td6
Operation of the cooling fan is controlled by the ECM. The ECM monitors Engine Coolant
Temperature (ECT) to determine fan speed. The ECM (C0606) provides a feed to the ECT
sensor (C0169) on an SU wire. The ECT sensor is a Negative Temperature Coefficient
(NTC) sensor. By measuring the voltage returned on an NG wire, the ECM can determine
engine coolant temperature.


When the ATC ECU engages the A/C compressor clutch, the ATC ECU (C1629) informs the
ECM (C0331) via the K bus on a WRY wire that cooling fan operation is required. The ATC
ECU also informs the ECM of the speed to drive the motor. For more information on A/C
operation, refer to the Automatic Temperature Control (ATC) or Automatic
Temperature Control (ATC) – Comfort section of this manual.
+AUTOMATIC TEMPERATURE CONTROL (ATC).
+AUTOMATIC TEMPERATURE CONTROL (ATC) – COMFORT.
The ECM (C0331) now provides a feed to the cooling fan control unit (C0005) on a BG wire.
This is used by the control unit to regulate the supply voltage from maxi fuse 61 of the
passenger compartment fuse box (C0581) on an RU wire.
'"

The electric fan speed is varied based on refrig pressure, and I am sure it should be running at a minimum slowly when the AC is on and vehicle is stationary when the viscous fan is running - it should be roaring when the viscous fan has dropped off - it is totally disabled over 70kph.

** With diagnostic equipment you can check the refrig pressure, and requested fan speed. If requested speed is >0% and it isn't spinning you have a problem.....
** When the TD6 is started cold the viscous fan is pretty much running at 100% (to remove moisture from engine bay) and it draws a lot of air through, however after the first couple corners it should drop off - stop and check what the Aux fan is doing after the viscus fan has stopped. Without a working aux fan the refrig pressure will be stupidly high.

The Aux fan on the TD6 is a common failure - IMO it is far more complicated than it needs to be, I had heap of problems with it on my old TD6 about 8-9 yrs ago.