Control Box

With thermosensor connector removed and a timing light attached to the high tension lead of the trailing distributor, proceed as follows:

Fig 1: Testing Control Box

Courtesy of MAZDA MOTORS CORP.

1. Make sure that timing light does not flash when engine speed is between 1600-4200 RPM, and that it starts to flash again at speeds in excess of 4200 RPM.
2. Connect an ammeter to the air control valve solenoid and to the anti-afterburn valve solenoid. Make sure that currer flow to both solenoids when engine speed is 800-4200 RPM and that current does not flow to either solenoid when engine speed is in excess of 4200 RPM.
3. Using a short piece of wire, connect both terminals of the thermosensor connector to each other in order to short circuit the connector. Make sure that timing light flashes at engine speeds between 1600-4200 RPM.
   Fig 2: Connector Short-Circuit

   Courtesy of MAZDA MOTORS CORP.
4. Remove wiring used to short circuit connector and connect thermosensor connector to the thermosensor. Attach an ammeter to the coasting valve solenoid and make sure there is no current flow to the ammeter at idle speed. At speeds of 1250-1550 RPM and above current should flow. When engine speed is gradually lowered to 1100-1300 RPM, current flow should stop.
   Fig 3: Testing Control Box

   Courtesy of MAZDA MOTORS CORP.