Cummins/Onan — Wiring Harness Check (Test M)
Testing & diagnosis
From a Cummins/Onan service manual covering: DL4, DL6, DL6T. Check it applies to your exact model before use.
Applies to: Cummins/Onan DL4, Cummins/Onan DL6, Cummins/Onan DL6T
Procedure
- Inspect all wires for breaks, loose connections, and reversed connections.
- Remove wires from terminals at each end and check each wire end to end for continuity or opens.
- Check each wire against each of the other wires for shorts or insulation breaks.
- Reconnect or replace wires according to applicable wiring diagram.
Tools required
- ohmmeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: Cummins/Onan DL6 →
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.