Any CIS Gurus?
 

1980 Euro S M28/11

Anyone know how to test the coolant temp sensor?

I also need to know how it's wired.

Is ther power at the sender when you turn on the key? What does it control?

Well... correct me if I'm wrong- but I think the CIS cars have 2 coolant temp sensors, one for the inside gauge and one to control the warm up regulator.

The temp senders are thermally activated resistors so they should have specific resistances at certain temperatures. Remove the plug to test the resistances.

the gray plug sender: "measure resistance direct off temperature sensor"
-10 C/14 F : 7... 12k ohms
+20 C/ 68 F : 2... 3k ohms
+80 C/ 250 F : 250... 400 ohms

the brown plug sender (colt start valve): see the pic below from the manuals:

http://forums.pelicanparts.com/uploa...1308641816.jpg

Current flows to the cold start valve whenever the starter is engaged, and if the temps drop below about 86 degrees (that's what your testing in the chart in Anthony's post), then the thermo-time switch grounds and allows the cold start valve to be energized.

If it's cold enough for the thermo-time switch to ground, then the "time" part of it will allow it to energize the cold start valve for about 10 seconds max in the coldest conditions before it de-energizes the cold start valve..

Besides testing like Anthony and RJM stated, test each connector on the thermotime switch for a circuit to ground. If the heating element has burnt and fell against the body of the switch, it could cause the cold start valve to run continuously.

Ok, thanks both of you. Where does the current come from? I have a current flow diagram. It's greek to me.

I located a guy that offered to look at it with me. I'm very relieved.