temp gauge pinned on hot when truck is cold

[toyotawild]

Ok this is an 87 turbo truck and the gauge cluster is swapped to an non tach style cluster.  The temp gauge on the thing is pinned as high as the needle goes before the truck is even warmed up.  Its like its just a lot more sensitive or something or the temp sending unit on the thermostat housing could be bad too I guess.  Anybody have any advice

[whokrz]

If the old gauge cluster had a tach and the new one doesn't then maybe the wiring is different?
Maybe trace the wire from the engine and see if it plugs into the right spot. 

[nuclearjunky]

Sending wire grounded somewhere?  Pull the wire off the sending unit and see if it bottoms, then ground it, it should peg out.