What triggers the engine fan on

Ac on or off, loaded or not, pulling or not makes no difference

 

Hi Mr Big,
You can wire in a switch for a manual fan override. The ECM should already be programed for it, find which input port will activate it. In all likely hood the wires are already in the dash. Take it to Dieselspec.ca they can do a printout of the parameters of your ECM. and activate the port you need. While your there have them program it to give you better fuel economy and a few other tricks of the trade.
ISF

 

The guys a right. The ECM will cycle the fan @ temp...the A/C will certainly turn on the fan...however, most Horton fans have a sensor ( 190,195,210,etc ) that cycle the fan. Sensors, & temps control. I REALLY like the Jake/Fan idea...make alot of sense!!!


Small discliamer: New engines NEED to run warmer than we're used to. Just like cars. Cumms / Cat now have 190-210 running ( thei IS RUNNING ) temps Generally speaking more heat IS more H.P. as long as the heat can be managed. IMHO.