Hi all, I have a 96 Sierra 1500 with the 4.3. I'm having a problem with the heater and temperature. The temperature barely gets high enough to register on the gauge. And the heater barely gets warm. Could this be a problem with the water pump, thermostat, heater core? Any help appreciated, TIA

I sounds like you have a thermostat that is not closing properly. I would start with changing the thermostat. It will probably fix the problem.

Yup, try the thermostat first and then move onto bigger things if the problems isn't solved.

Well since you say the heat doesnt get hot that pretty much rules out the gauge just going whack. Change the thermostat( $5 part) then see what happens