97 240sx help with temp sensor

[BoostedSilviaS14]

there is something wrong with the temp sensor on my 240. the temp sensor reads cold even when my car is warmed up. i drove for 30 minutes and the temp sensor still reads cold. it would barely budge. i do not know whats wrong with it but i know the cluster is still good, just the temp gauge is screwed up.

[rioredstang]

OK, first let me make sure we are looking at the same thing. The gauge on the dash uses a temp sending unit that has a single wire. The temp sensor for the computer has a (2) wire sensor.The temp sending unit for the gauge on the dash should be a yellow wire mounted close to upper radiator hose. Unplug the wire, gauge should go to cold, now touch wire to ground and gauge should go to hot. If it does then the wiring harness and dash are working and you have a bad sending unit. If not then something in the harness or instrument cluster have a problem.