If I have my radiator fan operating off of a toggle switch do I need the fan switch temp sensor between cylinders 6 & 8? Does the ECM use this for reference? The plug needs to be replaced and if I don't need it I'm not gonna replace it.

 

ECM does NOT use the switch in the pass side head. ECM only operates the PRIMARY fan,... the ECM CTS (Coolant Temp Sensor) is where the ECM gets it's temp readings from.

The switch in the pass side head only controls the SECONDARY fan.

The switch in the pass side head it a "switched ground" circuit. In the past; ( usually because the switch fails ) I've seen it modified by people with a toggle switch by cutting the wire at the switch, adding wire to it and running the wire into the cockpit to a toggle switch,.... and running the other wire from the 2-way toggle switch to ground so the toggle switch sends the "switched ground signal rather than the switch in the head. The rest of the system ( relay, wiring, ect...) would still need to be intact and functional for this basic modification to work.