why would i have no heat and my temperature gauge not work on my 98 isuzu hombre on 1998 Isuzu Hombre

I just changed the water pump, thermostat and temperature switch because I had a leak and was told it was the water pump. I have no leak now but my heat is still not working and neither is my temperature gauge. WHY??? Please help

Asked by for the 1998 Isuzu Hombre
possible air in system; possible broken/disconnected CTS or wire.
2 answers
Why , Because it wasn't diagnosed properly? Was the temp. guage working before? If so, make sure it's plugged in and no wire damage. Thermostat installed correctly , and system was allowed to warm up and purge all air out of system??? Air trapped in system will cause a no-heat condition sometimes.