have 91 chevy c2500 2wd 350 auto ac blower blows cool air after turned down
temp in cab no engine overheating has new water pump and t-stat. temp gauge
dances up and down from 180 to 210 but never over heats has plenty of
anti-freeze. i think these trucks had vacuum operated controls and that
the temp switch has stuck in the cool air area. am i wrong on this