Disconnect vacuum hose #2 from the vacuum manifold and connect a vacuum pump to the hose.
Turn on the ignition.
Measure the voltage between pins 1 (Green/Yellow (+)) and 32 (Black (-)).
If there is battery voltage, then see point A), if not, then point B).
A) Create a vacuum greater than 80 mm Hg.
Measure the voltage between pins 1 (Green/Yellow (+)) and 32 (Black (-)).
If there is voltage, then vacuum switch A should be replaced.
If there is no voltage, then vacuum switch A is normal.
B) Turn off the ignition.
Disconnect the 4-pin connector on the control box.
Turn on the ignition.
Measure the voltage between the Black/Yellow (+) and Green/Yellow (-) terminals on the main wiring harness.
If there is voltage, then vacuum switch A should be replaced.
If there is no voltage, then measure the voltage between the Black/Yellow (+) contact and ground.
If there is battery voltage, then you should repair the break in the Green/Yellow wire between the control box and terminal 1 of the control unit.
If there is no voltage, then you should repair the break in the Black/Yellow wire between fuse #1 (15 A) and the control box.