coolant temp sensor locations

[munkee]

I have a motor from an 89 in my 90 and I used all of the coolant hoses and wiring etc. On the 90 it has a coolant sensor in one of the metal lines that either goes to or from the heater core. The lines from the 89 don't have it. Is there another location for it on the 89 or should I just switch out the hoses?

 

[yamahaSHO]

There are 2 coolant temp sensor on the SHO motor. The sensor for the guage is just to the left of the T-stat, the sensor for the PCM is just to the right of the T-stat.

 

[munkee]

What is the one on the coolant line for then? The wire that plugs in to it branches out of the wiring for the wiper motor on the firewall and has the same type of plug as the one that goes to the vacuum canister on the back of the intake. Both of the sensors by the t-stat are plugged in but I don't get a reading at the gauge.

 

[SHOZ123]

That is the Cold Engine Lock Out (CELO) which keeps the heater fan from going into high speed when the engine is cold.

 

[rangerj]

MUNKEE,

The temperature "Sending Unit" is for the gauge and has one wire attached to it. Unplug the wire at the sending unit, set the ignition switch in the KOEO position, then ground the wire. The gauge should go up all the way (into the red).

If the gauge works, then the sending unit is bad. If the guage does not work check the wire for continuity between the gauge end and the sending unit end. If you do not get continuity the wire is either shorted or open.

If the wire is ok, then do the gauge tests recommended in the Helm manual, or copies of the tests in Chiltons, Mitchels, Motors Manual, etc. rangerj

 

[munkee]

Rangerj, thanks. I will give that a try. Shoz123, is it going to hurt any if I keep running it without that sensor?

 

[SHOZ123]

No you don't need the sensor. Mine's been broke since I got the car. You just have to manually turn the fan speed down when the engine is cold and the heat is in auto.