Re: 69 gauges again
On the coolant sensor in the head, I bet the sensor is bad but for giggles, warm up the engine and then test the sensor again. If the reading is the same, I would replace the sensor in the head.
You are on the right track.
Edit: I just pulled out a new consol gauge coolant sensor I have. Cold, it measures 750 ohms. I then put it in a cup full of hot water and it then measured 247 ohms.
Recheck your sensor after you bump the ohm scale up to 2000 ohms on your meter.
Also, look up how to use a DVM on google. I am pretty sure when you are testing circuits like this you don't want voltage running thru them as it will skew the readings. I always just disconnect the battery when doing these tests