| Number | X-pin, colour | Description |
|---|---|---|
| X18801 | 12-pin, blue | Plug connector On-board monitor control unit |
| Pin | Type | Description / Signal type | Connection / Measuring notes |
|---|---|---|---|
| 1 | E | Signal Locator lighting | Connector, instrument and locator lighting |
| 2 | M | Ground | Ground point |
| 3 | A | Signal, audio cassette, left + | Radio control unit |
| 4 | A | Signal, audio cassette, left - | Radio control unit |
| 5 | E | Signal NAV-bus | Navigation computer |
| 6 | E/A | K-bus signal | K-bus connector |
| 7 | E | Terminal 30 | Fuse F41 |
| 8 | Not used | ||
| 9 | A | Signal, audio cassette, right - | Radio control unit |
| 10 | A | Signal, audio cassette, right + | Radio control unit |
| 11 | E | Terminal R | Fuse F7 |
| 12 | Not used | ||