Cummins/Onan — Changing Control Accessory Panel (Groups 51 Through 55)
Repair & overhaul
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- Failure to remove AC power from the automatic transfer switch and to disable the generator set presents a serious shock hazard during this modification.
Procedure
- Open automatic transfer switch cabinet door.
- Move the operation selector switch to STOP.
- Disconnect the starting batteries.
- Remove AC voltage from the automatic transfer switch.
- Remove the twist-lock disconnect plug and open control accessory panel.
- Remove the external wires from TB1 and TB6, then remove the terminal blocks from mounting.
- Hold the flange edge of the control accessory panel's bottom hinge pin with a needle-nose pliers and remove screw from pin with a screwdriver.
- Carefully pull outward on bottom of control accessory panel until it clears cabinet.
- Lower control accessory panel from cabinet. Top hinge pin will come out with control accessory panel.
- Remove the top hinge pin from control panel and install on new panel if required.
- Lift up new control panel into cabinet, carefully engaging top hinge pin.
- Center the hole on the bottom control panel flange over the hinge pin.
- Insert the screw in bottom hinge pin and tighten with screwdriver and pliers.
- Install terminal boards TB1 and TB6 (from new control accessory panel). Connect loose wires in cabinet to terminal blocks as marked.
- Close panel, reconnect disconnect plug, restore AC voltage, reconnect batteries, move selector switch, close cabinet door.
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.