Cold Weather Modulator

Fig.4 - Cold Weather Modulator:

This modulator, Fig. 4, located in the air cleaner housing of some 1975-82 Ford vehicles, prevents the air cleaner door from opening to non-heated outside air at ambient temperatures below 55° F. At ambient temperatures above 55° F., the modulator is inoperative. During acceleration at ambient temperatures below 55° F., the modulator located in-line between the bi-metal sensor and vacuum duct motor, will close off vacuum to the motor and hold the duct open.