water temp gauge on my 2000 olds alero

okay

you cannot replace the sensor for the light
it interfaces with the ecm to turn fans on/set idiot light/etc
you would have to use some kind of t fitting and run both off the same port
which will be tough because of the design of the factory temp sensor
on a 3.4 it's located on the drivers side front of the intake
on a 2.4 it's located on what looks like a thermostat housing on the drivers side of the head