Midsize LTD L4-140 2.3L SOHC (1986)
Thermostatic Air Cleaner Vacuum Switch: Description and Operation
Air Cleaner Cold Weather Modulator
A cold weather modulator is some times used in addition to the air cleaner temperature control (bi-metal) sensor to control the inlet air temperature.
The cold weather modulator traps vacuum in the system, so the door will not switch to cold air when the vacuum drops during acceleration. The cold
weather modulator only works when the outside air is cold.
