hello everyone
whats the correct way to wire ecu fan control (a12) for cars that dont have a ecu fan control (most eu models) ?
i used to just run a wire from ecu pin a12 tapped to the green wire of the fan switch. and adjust fan control from software. it worked fine but im not sure of thats the correct way to wire, it, some sources says another relay is required,
thanks

 

 

Is the a12 pin not available or not active? Are you asking for another pin to wire it to?

 

a lot of EU cars did not have the wire from A12 to the temp switch for some reason.


​​​​​​​A12 runs in parallel to the Coolant Temp Switch, so either can turn on the existing relay in the underhood fusebox.

so what you describe is exactly how the OEM wiring works.
see attached diagram from the manual.

Fans page from the ETM for the 92-95 civic.