Rep Power: 0

I have a 1.8L 90 civic that I rebuilt the engine, and I can't get the temp gage to work. When starting the car the gage operate in the (-) negative position. I replace the temp sending unit in the head did not solve the problem. I thought to replace the gage with a aftermarket external gage, but could not get a probe or thread pattern to fit in the head. Any help is appreciated.

 
Rep Power: 234

Unplug the sensor and unplug at the gauge cluster. Then take your multi-meter and test for continuity (Ohms) of that wire. If no continuity, find the break in the wire or run a new one.

I can't be any more specific than that 'cause you have a swap and I don't know about the wiring for that.