87 s10

i pulled ou my heating/air switch to do a little work after reinstalling i can't get any air to turn on and its making a hissing type sound from the actual switch.. anyone got an idea??





thanks

i pulled ou my heating/air switch to do a little work after reinstalling i can't get any air to turn on and its making a hissing type sound from the actual switch.. anyone got an idea??





thanks

CHECK FOR PIN HOLE ON THE SWITCH, MAKE SURE NO CRACKS

i pulled ou my heating/air switch to do a little work after reinstalling i can't get any air to turn on and its making a hissing type sound from the actual switch.. anyone got an idea??





thanks

The switch uses engine vacuum to control the various vacuum motors used to operate the diverter valves inside the HVAC (heating, ventilation A/C) plenum. If the rubber gaskets/seals in the switch are worn & leaking (the hissing sound) then your system won't work correctly. You will need to replace the switch.... check rockauto.com...they have good prices on OEM parts (factory and aftermarket). Also, check to make sure the vacuum connection(s) to the switch are secure and not leaking.

mike
85S10