Originally Posted by
pennyman1
All a/c units on these trucks were addon units, either at the dock or at the dealer - so the a/c belt only runs the a/c. The bottom pulley on the crank has a second pulley added to it to spin the a/c compressor - not an issue to the truck not using a/c, but will be needed on the truck the a/c is going on. The idler pulley will also be needed to tension the a/c belt. The evap box can come out of the interior without affecting the heater - it is an addon also. The thermostat control unit should be on the evap box.