Cummins/Onan DL3 — Relay Checkout
Testing & diagnosis · Relays
For the Cummins/Onan DL3, from the Cummins/Onan service manual.
Applies to: Cummins/Onan L Series Diesel engine
Procedure
- Determine coil and contact terminals from the schematic diagram; numbers/letters are stamped on the relay.
- Apply rated voltage across the relay coil terminals; relay should activate if coil is okay.
- Connect voltage source to one side of relay contacts; connect voltmeter to other side and to voltage source.
- If voltage appears when relay energizes, contact is okay.
- Voltage reading appears in reverse order when checking normally closed (NC) contacts.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
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.