FJ40: temperature sending unit (3 Viewers)

[DennisGraham]

I have a two wire plug with a one wire sender from NAPA. Is there a two wire sender ? This is a 77'.

 

[spotcruiser]

That connector probably has a mating connector with two separate wires. I'm not sure about a '77, but you could have one wire for each of two temp sensors (one for gauge and one for emissions) or one wire for temp sensor and one wire for the idle solenoid.

If you have a wire from the DS fender going to the idle solenoid, then the two wires from the center of the firewall are probably both for temp sensors.

 

[spotcruiser]

It just occurred to me that one of the wires at the center of the firewall could also be for a cooling fan temp switch. The fan switch wire for a '76 came from the center of the firewall. The fan switch wire for a '78 came from the DS fender. I don't know about your '77.

Looking at a wiring diagram, the yellow wire should be for your cluster temp gauge.

 

[GA Architect]

FWIW - My '77 has a single white wire from the fire wall to the temp sensor.

 

[emac]

My 77 looks like GA architects. Single wire.

 

[spotcruiser]

California truck perhaps, DennisGraham? Just curious.

 

[sggoat]

FWIW - My '77 has a single white wire from the fire wall to the temp sensor.

View attachment 1383585

same here -- mine's a Ca rig