I keep the most common failure components stocked in my van because certain repairs come up so predictably I’d lose time driving to a supplier. When I show up to a rig and already know what’s wrong before I open the access panel — that’s not experience, that’s pattern recognition from seeing the same failure hundreds of times. The diesel heater glow plug and fuel pump are exactly that kind of repair on the Grech Strada — cold mornings, no heat, and an owner staring at an error code they’ve never seen before, but I’ve seen it so often I carry the parts before I even confirm the appointment. What makes this one matter beyond comfort is that a failed diesel heater in the wrong conditions isn’t just an inconvenience — it’s a safety issue, and a misdiagnosis that replaces the wrong component wastes both money and time you don’t have when you’re parked somewhere cold. This guide walks through exactly how I diagnose and service this system in the field, so you can approach it with the same confidence I do when I pull up to the rig.
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 Issues
Start by connecting your digital multimeter to the diesel heater’s 12V power supply to verify adequate voltage is reaching the unit. Check the LCD control panel for error codes or malfunction indicators, which will help you identify whether the glow plug or fuel dosing pump is the primary culprit.
Step 2: Disconnect Battery and Fuel Supply
Turn off your Class B van’s main battery disconnect switch and allow the diesel heater to cool completely for at least 30 minutes. Locate the fuel line connecting to the heater and carefully disconnect it, positioning a small container beneath the fitting to catch any residual diesel fuel.
Step 3: Remove Old Glow Plug Assembly
Access the glow plug connector at the top of the combustion chamber and disconnect the electrical terminal by gently twisting counterclockwise. Using a ceramic glow plug socket and ratchet, carefully unscrew the old glow plug and inspect the combustion chamber for carbon buildup or corrosion around the mounting area.
Step 4: Replace Fuel Dosing Pump Unit
Locate the fuel dosing pump mounted on the heater’s fuel delivery system and disconnect both the electrical connector and fuel lines. Install the new 12V diesel heater fuel dosing pump, ensuring all fuel line connections are hand-tightened first, then secured with a wrench to prevent leaks.
Step 5: Install New Ceramic Glow Plug
Insert the new Webasto/Espar ceramic glow plug into the combustion chamber and hand-thread it until snug, then use your socket wrench to tighten to approximately 10-12 Nm. Reconnect the electrical terminal and ensure it clicks firmly into place before moving to the next step.
Step 6: Replace Fuel Filter and Lines
Swap out the old inline diesel fuel filter with a new one, ensuring the flow arrow points toward the heater unit. Cut approximately 2-3 feet of the 4mm diesel fuel line silicone tubing and use hose clamps to secure all connections at both the fuel tank feed and heater inlet.
Step 7: Test Heater System Operation
Reconnect the battery and power up the LCD control panel, setting it to a low heat output level and observing for 5-10 minutes. Use your digital multimeter to confirm the glow plug receives 12V during startup, and listen for the fuel pump’s distinctive clicking sound, indicating successful fuel dosing and combustion chamber ignition.
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 |