Program Vacuum Disc Switch

Remove control protection cover (Riviera), instrument panel cover and right defroster hose (all other models), then proceed as follows:

1. Start engine so that vacuum supplied to power side of PVA, place control in Maximum A/C, slowly reduce vacuum to pilot side of PVA to 3.0" Hg.
2. Loosen adjusting screw and adjust switch operating link on PVA-to-temperature door linkage for an A/C to Heater mode shift, tighten adjusting screw.
3. Increase regulated vacuum to pilot side of PVA to; 8" Hg. and check for maximum A/C and recirculated air.
4. Slowly reduce vacuum to pilot side of PVA and check for change to outside air and for vacuum supply to water valve before temperature door moves from maximum A/C position. If Air Intake (A.I.) Door does not change from recirculated air to outside air, or if vacuum is not applied to water valve, before movement of the temperature door, readjust or make repairs as necessary to obtain proper operation.