radiator fan on constant

as title says my fans on constant,ive looked under rad and theres a white connecter with two wires hanging
loose at the bottom,so its possable that last owner took it off because of over heating or its come loose.
have any of you guys had any expeirance of this.
dont know if i should leave well alone or what.

Fan on constantly will:-

Ruin the fan
Reduce battery lifespan
Reduce alternator lifespan
Reduce fuel efficiency

How long have you had the van?
What does the temperature gauge say?
How much water is in the header tank?
What colour is the water?
How much water is there under the metal cap?

had the van a week and it not using water and its pink colour.
the temp stays at the middle.

I think the fan switch in the rad has failed and the conector has been shorted to keep the fan on, so get a new switch and plug it all in properly.

thanks ,will give it a go at plugging in loose one first.