Federal Vehicles

1. Disconnect the Digifant control unit harness connector.
2. Connect a suitable volt/ohm meter between terminal 14 of the Digifant control unit harness connector and ground.
3. Turn the ignition switch "ON".

^ The correct measurement should be battery voltage.

If the correct measurement is obtained the power supply relay is OK.
If the correct measurement is not obtained continue.

Relay Locations:

4. Turn the ignition "OFF" and remove the power supply relay.
5. Switch the ignition "ON" and measure the voltage at the terminals of the fuse box which correspond to terminal 30 and terminal 86 of the power supply relay.

^ The correct measurement should be battery voltage at each terminal.

6. Measure the voltage between the terminals of the fuse box which correspond to terminal 85 and 86 of the power supply relay.

^ The correct measurement should be battery voltage.

If the correct measurement is not obtained, the fuse box or wiring is defective.

If the correct measurements are obtained check the resistance between terminal 14 of the Digifant control unit harness connector and the terminal on the fuse box which corresponds to terminal 87 of the power supply relay.

^ The correct measurement should be less than 0.5 ohms (continuity).

If the correct measurement is not obtained, repair or replace the harness or fuse box as necessary.
If the correct measurement is obtained, replace the power supply relay.