Put the intermediary wiring (5) into position between the connector (6) of the triggering contact holder and the vehicle harness. Ensure that the inhibition cham «a» on the 3-way connectors (3) and (4) correspond. - Run the engine at 1500 rpm approx. - Connect the voltmeter. The «—» on plug (2) (black ) The «+» in turn on plugs (1) (red).