Hello everyone!

I have a question for you... I've replaced the thermostat in my 1994 Nissan Sentra and I've also tried to replace the temp. sending unit. When I put the new sending unit it, it sent the temp. gauge straight up to hot. I put the old sending unit in and the temp. gauge went back to normal. What could be the cause of this?

you have an internal short in the sender or you have the wrong sender. if you were to take the wire that plugs into the senser and ground it to the manifold it would peg to hot as well. thats how it works.

Why are you trying to fix something that isn't broke?