Air Con Fan control issue

[Ben Jones]

Hello again chaps,

I need to find an efficient way to control my air con fan.  As its currently set as an air con fan output - the fans would run constantly when the ac request is on.  I would like them to be triggered by a seperate input (from an A/C pressure switch) so they will cycle as needed.

It seems the best way to solve this would be to change the trigger in the 'Air con fan' output to a digital input instead of the ac request.

Is this possible?  I have other ways around the problem but so far none would beat this scenario.

[Ben Jones]

I considered changing the AC fan to a GP output, but then theres no hysteresis for engine coolant temp.  My AC fan is also needed as the engine cooling fan.  The AC fan ouput triggers both fans at low, then theres a seperate output used to trigger high speed operation at a higher coolant temp.

[Simon]

You could set the fan to be controled off a GP out put. Then use a virtual aux as one of the conditions for the GP. This will give all manner of configurations to switch off.

[Ben Jones]

Thanks for the idea Simon.  I hadnt considered using a virtual aux.

Final solution was to use the fan output as a gp output. Triggered 1 as virtual aux (configured as an engine cooling fan) or Trigger 2, a digital input (a/c pressure switch).  The a/c clutch will then be triggered by an a/c request digital input.  This satisfies all of my requirements without creating any new issues.