Backup Lamps Inoperative P72
Circuit Description
With the ignition switch in RUN or START, voltage is supplied through the TURN-B/U fuse to the transmission position switch or the backup light switch. Whenever the gear selector lever is shifted to R (Reverse), the transmission position switch or the backup light switch closes and voltage is supplied to the backup lights and the lights go on.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Do the backup lamps come on? | -- | System OK | Go to Step 2 |
2 | Probe the LT GRN (24) wire at C101 with a test lamp. Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 3 |
3 | Probe the LT GRN (24) wire and C204 with a test lamp. Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 5 |
4 | Locate and repair the open circuit in the LT GRN (24) wire between C101 and C204. is the repair complete? | -- | Go to Step 1 | -- |
5 | Probe the LT GRN (24) wire and the backup lamp switch. Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 7 |
6 | Locate and repair the open circuit in the LT GRN (24) wire between the backup lamp switch connector and C204. Is the repair complete? | -- | Go to Step 1 | -- |
7 | Locate the open circuit in the DK BLU (75 or 38) wire between the backup lamp switch and the fuse block. is an open circuit found? | -- | Go to Step 8 | Go to Step 9 |
8 | Repair the open circuit in the DK BLU (75 or 38) wire between the backup lamp switch and the fuse block. is the repair complete? | -- | Go to Step 1 | -- |
9 | Replace the backup light switch. is the repair complete? | -- | Go to Step 1 | -- |
10 | Refer to the coach manufacturer's repair manual in order to diagnose and repair the system. Is the repair complete? | -- | System OK | -- |
Backup Lamps Inoperative P92
Circuit Description
With the ignition switch in RUN or START, voltage is supplied through the TURN-B/U fuse to the transmission position switch or the backup light switch. Whenever the gear selector lever is shifted to R (Reverse), the transmission position switch or the backup light switch closes and voltage is supplied to the backup lights and the lights go on.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Do the backup lamps come on? | -- | System OK | Go to Step 2 |
2 | Probe the DK BLU (22B) wire at the interface panel with a test lamp. Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 3 |
3 | Probe the DK BLU (22B) wire at C204 with a test lamp. Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 5 |
4 | Locate and repair the open circuit in the DK BLU (22B) wire between C204 and the interface panel. Is the repair complete? | -- | Go to Step 1 | -- |
5 | Probe the DK BLU (22B) wire at the backup lamp switch connector (V.I.M. for MD3060). Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 7 |
6 | Locate and repair the open circuit in the DK BLU (22B) wire between the backup lamp switch connector (V.I.M. for MD3060) and C204. Is the repair complete? | -- | Go to Step 1 | -- |
7 | Locate the open circuit in the DK BLU (2) wire between the backup lamp switch and the switched circuit breaker. Is an open circuit found? | -- | Go to Step 8 | Go to Step 9 |
8 | Repair the open circuit in the DK BLU (2) wire between the backup lamp switch and the switched circuit breaker. is the repair complete? | -- | Go to Step 1 | -- |
9 | Replace the backup light switch. Is the repair complete? | -- | Go to Step 1 | -- |
10 | Refer to the coach manufacturer's repair manual in order to diagnose and repair the system. is the repair complete? | -- | System OK | -- |
