Is it the radiator temp sensor or the one on the back of the cylinder head?

 

What car? My 2026 fans are controlled by the ECU. I think there's a thermostatic switch in the bottom of the radiator on non-DBW cars. Via some relay I assume. The AC switch turns them on regardless of engine coolant temperature.

I had no idea there was another sensor on the back of the block. Cursory glance at the Service Manual p 10-13 etc doesn't mention one.

-- Chuck

 

On pre DBW cars the radiator does not have a temp sensor, it's a temp switch (199F or 93C) which controls the relay to radiator fan.
DBW cars I believe have a temp sensor there instead and controls fan via ecu.

 

I see, thanks, then it's the radiator switch that turns the fans on, not the sending unit in the back of the head.

 

Thanks, I didn't see that last one when I looked!

-- Chuck