VS 5ltr Themo Fan issue

[Bongo]

OK what controls the thermo fan, my reason is it cuts in and out all the time BUT won't stay on when it counts, or how can I get this to come on as it should and stay on

[hako]

By thermo fan I gather you mean the electric fan?....if so it will be turned on by the coolant temp sensor which tells the ECU which will power a relay - if it's cutting out when it shouldn't be then I'd check the relay first.
Turning the A/C also should make the fan come on.

[VrWagz1]

Depends also, are you talking bout the little tiny one on the front or have you done a thermo fan conversion and tossed the clutch fan. If so how did you set them up....Did you use an external trigger cct or get the memcal modified to run the fans?

[IvanTheTerrible]

The fan on the front of the condensor is a condensor fan and is controlled by a pressure swith in the aircon line. When the condensor gets to hot it turns the fan on. Nothing to do with engine temp.



Ian

[BlackVXGTS]

Wrong. The ECM/PCM will turn on the fan under the following circumstances:
- if the coolant temperature exceeds 110 C (runs until the coolant temp is below 105 C),
- if it detects a coolant temperature sensor failure,
- if the AC request signal is received and the vehicle speed is less than 64kph,
- if field service mode is active - ignition on, engine stopped, and DLC diagnostic "test" enable terminal earthed

In addition, as you point out, the engine cooling fan relay can also be energised by the AC pressure switch.