| 1 | Check the protected power supply from the instrument panel. Connect an Examiner in Voltmeter mode with the positive probe connected to pin 3 and the negative to pin 2 of the 9-way auxiliary instrument connector. With the key on, the voltage reading should be approximately 12 volts. | 1.Restore the +12V power connection.2. Restore the earth connnection across the instrument panel and auxiliary instruments. If the power supply is not OK, replace the instrument panel. If OK, replace the auxiliary instruments. |
| 2 | Check serial line 1. Disconnect instrument panel connector C and the 9-way auxiliary instrument connector: Check the continuity of the wiring between pin 1 of instrument panel connector C and pin 1 of the auxiliary instrument connector. Check the line earth insulation. | Restore the continuity/insulation of the serial line. If the checks on the power supply and serial line are OK, replace the auxiliary instruments. If there is no serial line signal at the panel output, replace the instrument panel. |