Genuine Onan generator-mounted start/stop rocker switch for select RV QG, KY, and HGJ series generator control panels.
The Cummins Onan 308-1038 is a replacement rocker switch used at the generator control panel on select Onan RV generator models. If the original start/stop switch is cracked, worn, sticking, intermittent, or no longer responding properly, replacing the switch can help restore normal local generator control.
This switch is commonly listed for Onan RV QG 2500 and RV QG 4000 Spec J and newer applications, as well as select KY and HGJ series generators. This is the rocker switch on the generator itself, not the remote interior start/stop panel.
Replacement rocker switch for generator-mounted start and stop control
Designed for compatible Onan RV generator control panel applications
Commonly listed for select RV QG, KY, and HGJ generator models
This is the switch on the generator, not the interior remote panel assembly
This rocker switch is not universal for every Onan generator. Cummins lists it for RV QG 2500 / 2.5HGJBB and RV QG 4000 Spec J and newer models, while other RV parts references list it for Onan KY Spec J and newer plus select HGJAA, HGJAB, and HGJAC applications. Before ordering, verify your generator model, spec letter, and existing switch style. This part is for the generator-mounted control panel switch and does not replace an interior remote panel, remote harness, or generator control board.
Before Starting: Turn off the generator, allow it to cool, and follow all RV/generator electrical safety precautions before servicing the control panel. Basic Replacement Steps: 1. Confirm Compatibility: Verify generator model, spec letter, and existing switch style before removing parts. 2. Disconnect Power: Disconnect generator starting power as required by the service procedure. 3. Access Control Panel: Remove the necessary generator control panel cover or access panel. 4. Document Wiring: Take a photo of the existing switch wiring before disconnecting terminals. 5. Remove Old Switch: Carefully release the old rocker switch from the panel opening. 6. Install New Switch: Connect the wiring to the replacement switch in the same arrangement and seat the switch in the panel. 7. Test Operation: Restore power and confirm that the generator starts and stops properly from the local switch.
Package Contents: • Cummins Onan 308-1038 rocker switch NOT Included — May Also Need: • Interior remote panel • Remote wiring harness • Fuse or fuse holder • Generator control board • Control panel cover or trim • Additional wiring terminals or connectors This listing is for the rocker switch only. Reuse existing serviceable wiring and hardware unless replacement parts are required.
To confirm compatibility before ordering, have the following ready: • Generator model number • Spec letter • Serial number • Existing switch part number, if visible • Whether the switch is on the generator or inside the RV Why this matters: Onan generator switches and remote panels can look similar in function but are not always interchangeable. Matching the generator model/spec and switch location helps avoid ordering the wrong control part.
Match this switch by generator model/spec and switch location. The 308-1038 is for the generator-mounted rocker switch, not the interior remote start/stop panel.
If the generator does not respond from the local switch, inspect the switch, wiring terminals, fuses, battery voltage, and generator-side control circuit before replacing parts.