Cummins/Onan — External Wake Tests
Testing & diagnosis · External wake circuit (J5/J6)
From a Cummins/Onan owner's manual covering: 1.5HJBAA, 2.0HJBAA, 2.5HJBAA, 3.0HJBAA. Check it applies to your exact model before use.
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Procedure
- Verify that the jumper across the left two pins of connector J6 has been removed; if not, the test is not necessary.
- Turn OFF the AC circuit breaker supplying power to the Inverter-Charger.
- Connect the batteries and check for 12 VDC across the Inverter-Charger terminals.
- Disconnect the wire harness from J5 and press the INVERTER ON/OFF button; the Inverting Indicator Light should remain off and there should be 0 VAC at the output.
- With J5 still disconnected, turn ON the DC load disconnect switch; check for 12 VDC across J5-3 (B+) and J5-7 (B-).
- Plug in the J5 harness, turn ON the DC load disconnect switch and press INVERTER ON/OFF; the Inverting Indicator Light should come on and 120 VAC should be at the output.
- Turn OFF the DC load disconnect switch while Inverting; AC output should go to 0 VAC and all LEDs should turn off.
- With the DC load disconnect switch OFF, connect AC power and enable Charging; verify the Charging Indicator Light comes on.
Tools required
- voltmeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- J5-3: External Wake Signal (12 VDC); J5-7: Ground for External Wake Signal
Source: Cummins/Onan owner's 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.