Cummins/Onan — Relay Checkout
Testing & diagnosis · Start disconnect relay
From a Cummins/Onan service manual covering: 0.6MAJ, 1.0MAJ, 1.5MAJ, 1.5MAJ-224R, 1.5MAJ-232R, 2.5MAJ. Check it applies to your exact model before use.
Applies to: Cummins/Onan 2.5MAJ
Procedure
- Remove relay from circuit.
- Place 12 volts on one side of relay coil and ground the other side. If relay activates it is operating.
- Place a 12 volt source to one side of the contacts.
- Place voltmeter to other side of relay contact and to ground. If 12 volts present when relay energized, relay is good.
- If relay has more than one set of contacts, each set must be checked in this fashion.
Tools required
- voltmeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 12 volts
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.