just bought a P-reg 1997 escort 1.6 16v lx 5 dr for my g.f, the temp gauge isnt working at all, and the fan kicks in when hot, any ideas what it could be?

at the switch located at right hand side of engine where the top hose connects, ive tried bridging the connections to see if the gauge moves, but nothing hapens, tested to see if there was power, brown wire is earth, and white wire there is nothing, there is also a switch on the top hose itself but havent tested anything on it, as you can tell im really unsure what it could be.