🚗 Classic Fault — Mercedes-Benz W115 (1968–1976)
Fuel sender unit failure — inaccurate gauge
💰 Estimated Repair Cost
$50 – $120 USD
Parts and labour estimate
🔧 Tools Required
Multimeter, sender removal wrench
📋 Overview
The fuel level sender unit develops a corroded resistance wire or seized float arm. The fuel gauge reads incorrectly — often stuck at empty or full.
🩺 Symptoms
- Fuel gauge always reads full or empty
- gauge reads inaccurately
- cannot trust fuel level
🔍 Possible Causes
- Corroded sender resistance wire
- seized float arm
- sender wiring fault
🛠️ Diagnosis Steps
Disconnect sender lead. Measure resistance at tank — should vary from approximately 10 to 180 ohms through full travel.
✅ Most Confirmed Fix
Replace fuel sender unit. Fit new sender seal.
74% of users confirm this fix worked (17 reports)
🏷️ Parts Needed
Fuel sender unit for W115
🔗 Other Mercedes-Benz W115 Faults
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