[Mitcha]

Hi All, have bought an SJ70 with poorly fitted G13B and am in the process of sorting the wiring. On the rear of the head I have 2 temp sensors with single blade terminals on them. One in the thermostat housing and one in the bottom of the head itself. Wire was connected to the thermo housing sensor and temp gauge seems to work... but what is the other (bottom of head) one for? TIA.

[fordem]

Assuming the DOHC engine, there are three temp sensors, one for the ECU (2 wire), one for the gauge (1 wire) and the third is a switch (1 wire) that is connected to the a/c system - if the a/c amp senses high coolant temperature it locks out the compressor & switches the condenser fan on to assist with air flow through the radiator.

[Mitcha]

Thanks Fordem, I actually have 2 single pin temp sensors so i Guess one of them is just blocking a hole.

[fordem]

The a/c temp switch looks like a gauge sensor but doesn't have a variable output - it's either on or off.

[Mitcha]

Ahhh OK. its beginning to make sense. I have 4 sensors at the back of the head. 2 single wire plugs and 2 twin wire plugs, one blue which goes to the ECU and one yellow which I assumed would be for a thermo fan? Not sure because it is not connected to anything and thermo fan is wired to IGN.