Hi, I'm trying to find the coolant sensor on this engine. That might sound like a silly thing to have trouble with, but I can see two things that look like the candidate, and neither are it. The actual problem I am having is that there is no heat and the temp gauge doesn't move. To me that says "thermostat", so of course I want to do that, but I also wanted to replace the sensor at the same time. That made sense until I tried to find it, and couldn't, and now I'm annoyed. I have found one sensor mounted on the thermostat housing - the wire routing and colour suggests this one is to do with the glow plugs. It has no continuity to the sense wire on the temperature gauge. This sensor has a single connector on it (some of the ones that pop up online have multiple connectors). The only other thing that looked like a sensor was towards the rear of the engine, which appears to be an oil pressure switch. No continuity. According to my wiring diagram (and the gauge), I am looking for a blue/lilac wire. I really thought it was on the thermostat housing, but there is only one sensor there that I can see, and that doesn't seem to be it. Can anyone help?