Every RV brand has a price point where the build quality starts compromising. I’ve bought rigs at every level, from entry-level travel trailers to high-end Class A coaches, and the failure patterns are consistent: manufacturers save money in the same places every time, and those are the systems that need attention first. On the Winnebago Solis, the diesel heater is exactly one of those systems — it’s a brilliant feature for shoulder-season camping, but the glow plug and fuel pump are consumable components that get zero attention from most owners until the unit throws a fault code at 11 PM in a 28-degree campsite. A failed glow plug means the heater can’t ignite, and a dying fuel pump means it’ll start once, maybe twice, then quit entirely — both failures feel catastrophic in the moment but are completely serviceable if you know what you’re doing. This guide walks you through the diagnosis and fix the same way I’d do it on a rig I’m turning around for resale — no shortcuts, no guesswork.
Parts & Tools You’ll Need
- Webasto / Espar ceramic glow plug
- Diesel heater fuel dosing pump (12V)
- Inline diesel fuel filter
- Diesel heater LCD control panel
- Combustion chamber blower motor
- Intake & exhaust silencer kit
- Diesel fuel line silicone tubing (4mm)
- Digital multimeter (auto-ranging)
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Step-by-Step Repair Guide
Step 1: Diagnose Heater Malfunction & Safety
Start by connecting your digital multimeter to the glow plug terminals to verify voltage output—you should read approximately 12V when the heater is powered on. If voltage is absent or the heater won’t ignite after multiple attempts, you’ve confirmed the glow plug has failed and requires replacement; also check that your house battery is fully charged and all connections are clean before proceeding.
Step 2: Disconnect Battery & Drain Fuel
Disconnect the negative terminal of your house battery to prevent electrical shorts during component removal. You’ll need to carefully drain the diesel fuel from the heater’s fuel line into a suitable container by opening the fuel line at the dosing pump connection point, allowing gravity to empty the system completely.
Step 3: Remove Glow Plug & Combustion Chamber
Locate the glow plug mounted in the combustion chamber access port and carefully unscrew it using a socket wrench—be gentle as the ceramic element is fragile. Once removed, inspect the combustion chamber for carbon buildup and corrosion, cleaning it lightly with a soft brush before installing your new ceramic glow plug and tightening it to manufacturer specifications.
Step 4: Replace Fuel Dosing Pump Assembly
Disconnect the fuel lines from both the inlet and outlet ports of your existing dosing pump, noting their positions for reassembly. Install your new 12V diesel heater fuel dosing pump by reversing the removal process, ensuring all fuel line connections are tight and secure to prevent leaks during operation.
Step 5: Install New Fuel Filter & Tubing
Replace the inline diesel fuel filter with your new unit, positioning it between the fuel tank and the dosing pump to protect against contamination. Cut a fresh section of 4mm silicone tubing and connect it securely to both the filter outlet and pump inlet, using stainless steel hose clamps on each end.
Step 6: Reconnect Combustion Blower & Controls
Reinstall the combustion chamber blower motor and verify all wire connections are properly seated in their harness connectors. Connect your diesel heater LCD control panel to its wiring harness, ensuring the display powers on when you reconnect the house battery and shows no error codes.
Step 7: Test Heater Operation & Monitor Performance
Reconnect your house battery and power on the diesel heater through the LCD control panel, listening for the familiar ignition sequence and checking that warm air flows from the output vents within 30 seconds. Use your multimeter to verify the glow plug receives 12V during startup, monitor fuel pressure at the pump for approximately 1 PSI, and run the heater for 10 minutes to confirm stable operation without error codes on the display.
Recommended Parts
| Part | Link |
|---|---|
| Webasto / Espar ceramic glow plug | View on Amazon |
| Diesel heater fuel dosing pump (12V) | View on Amazon |
| Inline diesel fuel filter | View on Amazon |
| Diesel heater LCD control panel | View on Amazon |
| Combustion chamber blower motor | View on Amazon |
| Intake & exhaust silencer kit | View on Amazon |
| Diesel fuel line silicone tubing (4mm) | View on Amazon |
| Digital multimeter (auto-ranging) | View on Amazon |