Distributor Modulator: Description
The electronic distributor modulator system controls emissions by eliminating vacuum advance below 23 miles per hour on acceleration, and below 18 miles per hour on deceleration. It is used on Econoline window vans, and F-100 2-wheel drive trucks. The four major components of this system are the speed sensor, the thermal switch, the electronic control module, and the distributor vacuum control valve, also known as a ported vacuum switch (PVS). The thermal switch is located in the right or left door pillar, the speed sensor is in line with the speedometer cable, and the control module is mounted under the dash panel. The ported vacuum switch is threaded into the coolant outlet elbow.