Honda 37800-ZA0-003 Solenoid Thermostat Switch

The Honda 37800-ZA0-003 Solenoid Thermostat Switch is a genuine OEM component designed for EL5000, ES6500, and EX5500 generators and the GX360 horizontal shaft engine. As an authentic Honda part, it meets the original design specification and installs directly in place of the worn or failed unit. Confirm your unit's serial number against the fitment table before ordering, as Honda supersedes parts at serial breaks and this switch must match your exact production range.

Key Features

• Genuine OEM Switching Accuracy — sourced directly from Honda, this switch delivers the precise actuation threshold the original thermal protection circuit was engineered around, keeping the generator or engine operating within its designed temperature limits.
• Direct OEM Replacement — built to the same connector, thread, and calibration spec as the original, this part slots in without modification, restoring the thermal shutoff function exactly as Honda intended.
• Broad Fitment — covers EL5000, ES6500, and EX5500 generators as well as GX360 horizontal shaft engines; check your serial number against the fitment table to confirm the correct application.
• Serial-Range Verification Recommended — Honda issues part supersessions at specific production breaks, so always verify your machine's serial number against the compatibility table before finalizing your order.

A solenoid thermostat switch is a thermally activated electrical switch that monitors operating temperature and triggers a solenoid-controlled response — typically cutting power or shutting the engine down — when a preset threshold is exceeded. On Honda generators and engines, this switch is a key part of the thermal protection system, guarding against overheating damage to the alternator windings or engine internals. When the switch fails or loses calibration, the machine may shut down prematurely under normal load, fail to shut down when genuinely overheating, or develop intermittent electrical faults that are difficult to trace.

Part Details

Compatibility & Fitment

Verify Before You Order

Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.

Why Buy From DHS Equipment

Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.

Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.