Complete repair guide for the Roadtrek Zion – Diesel Heater Glow Plug & Fuel Pump Service. Follow these steps to diagnose and fix the issue yourself.
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)
Disclosure: This post contains affiliate links. We may earn a commission on qualifying purchases at no extra cost to you.
Step-by-Step Repair Guide
Step 1: Diagnose Heater Issues and Prepare
Start by connecting your digital multimeter to the diesel heater’s 12V power supply to confirm voltage is reaching the system—low voltage indicates potential battery or electrical issues. Disconnect the negative battery terminal and allow the heater to cool for at least 30 minutes before proceeding with any component removal to prevent burns or electrical shock.
Step 2: Remove Old Glow Plug Carefully
Locate the ceramic glow plug in the combustion chamber head and use a properly-sized socket wrench to carefully unscrew the old plug, working slowly to avoid damaging the threaded hole. Inspect the removed glow plug for carbon buildup or corrosion, as this indicates combustion issues you’ll want to monitor after installation.
Step 3: Replace Fuel Dosing Pump Assembly
Disconnect the fuel line connectors from the old 12V dosing pump and unbolt it from the heater unit using your socket set. Install the new fuel dosing pump in the same orientation, ensuring all fuel line connections are secure and the silicone tubing shows no cracks or damage.
Step 4: Install New Ceramic Glow Plug
Screw the new Webasto/Espar ceramic glow plug into the combustion chamber head, tightening it firmly but not excessively to avoid stripping the threads. Reconnect the glow plug electrical connector, ensuring the connection clicks firmly into place.
Step 5: Replace Inline Diesel Fuel Filter
Locate the inline diesel fuel filter in the fuel line between the tank and heater, then disconnect both fuel line connections using a wrench to catch any spilled fuel. Install the new filter in the same direction as the original (note the flow arrow on the filter housing) and reconnect both fuel lines securely.
Step 6: Inspect Intake and Exhaust Silencers
Check the intake and exhaust silencer components for cracks, corrosion, or loose connections, as compromised silencers reduce heater efficiency and increase noise levels. If needed, disconnect the silencer kit bolts and replace with the new intake and exhaust silencer kit, ensuring all connections are airtight.
Step 7: Test Heater System Functionality
Reconnect the negative battery terminal, then power on the LCD control panel and set the heater to its lowest setting to begin a five-minute warm-up cycle. Use your digital multimeter to verify the glow plug receives power during startup, and listen for normal combustion sounds and verify exhaust airflow to confirm proper operation of all replaced components.
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 |