Temp Guage not working.....

[zippee]

My temp guage has stopped working, it occasionally gets up to 50 but soon drops to zero when moving. The fans come on properly when in traffic and the engine is certainly hot so looks like either the guage or sensor.
Does anyone know where the sensor is for the guage? I replaced my coolant temp sensor about 2 months ago to help cure a rough idle, is this the same sensor as for the guage?

[gf350]

Its on the front of the inlet manifold near the thermostat, it is positioned horizontally facing into the front of the engine and has one spade connector on it with (I think) a green wire comming off it.
I had mine changed at the service as it was reading a bit low (but not that low) and cleaning the connector made no difference.
It was well hidden on my chim though, but I've got aircon which adds a few extra pipes around there.
You can get a wire from modwise to use the spare temp sensor on the top right front of the inlet manifold (much easier to get at), I was going to get one but ended up replacing it as I was having the thermostat changed anyway.
My guage is now spot on compared to a digital thermometer.
I'd say the chances are its the same thing on yours, if I were you I'd get the modwise connector for now and then get it fixed at the next service.
Might also be an air lock???
Cheers,
GF