Today at Atelier Kaz - ex-Honda R&D, F1, Indy/CART engineer

As a side note, there are 3 temperature sensors on the cooling system.

This is the coolant temperature sender unit. It is the sensor for the coolant temperature gauge inside the dash and the sensor is mounted on the water passage that we saw earlier.





Next is the TW sensor for engine control. It's the one with round 2pin grey connector in the middle of this photo. It's located below the EGR valve and this is the one used for several engine control software modules related to the fuel timer and IG control.





The 3rd one is the thermo sensor at the thermostat cover. This is the one related to the radiator fan control.

All three sensors operate independently so even if your gauge may not be showing the correct temperature, the rad fan and engine control won't be affected.

There is a unit inside the cabin behind the left side seat called Fan Control Unit and this could experience soldering crack (like the Main Relay on many Honda/Acura models) resulting in all sorts of strange behaviour with the radiator fan.
Almost always when it fails, it will switch on the rad fan and both condenser fans when you put IG switch in P2 (ON position) even when the engine is cold and not even started over night.


Kaz