Originally Posted by pawoSD

1. Thermostat housing - sensor for the climate control cutout (when the temp rises it allows the blower to come on when coolant is 38C or above)

2. On the side of the engine - This is the temperature sender for the engine, it feeds the gauge on the instrument cluster

3. On top of the intake manifold - I think this is the temperature sensor for the glow plug relay, the temp it senses determines how long the "glow light" on the dash comes on. I may be wrong....officially I don't know exactly what it is.