Mercedes E420 Fuel Pump Relay Parts
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Mercedes E420 fuel pump relay typically cost between $9.59 and $41.99.
Where Is The Mercedes E420 Fuel Pump Relay Located?
The Mercedes E420 fuel pump relay sits in the fuse and relay box, which can be behind the rear passenger seat in the trunk or under the hood, depending on your model year. Pop the cover, and you’ll see a cluster of fuses and relays, usually with a diagram inside the lid. The fuel pump relay is a rectangle-shaped piece, sometimes gray or black, and it’s labeled with part numbers. If you don’t spot it right away, check your owner’s manual or a shop manual for a diagram that matches your car. Before pulling the relay, disconnect the battery to stay safe.
What Are The Symptoms Of A Failing Mercedes E420 Fuel Pump Relay?
When the Mercedes E420 fuel pump relay goes bad, you might struggle to start the engine—it cranks but doesn’t catch. Sometimes the car cuts out while driving as if it lost all fuel. The relay could work on and off, so the car runs fine one day and won’t start the next. You may also notice slow starts, sudden stalls, or rough acceleration. If you turn the key but don’t hear the fuel pump buzz, a failing relay is high on the suspect list.
How Do I Test The Mercedes E420 Fuel Pump Relay?
To test the Mercedes E420 fuel pump relay, pull it out of the relay box and inspect for green corrosion or burn marks on the pins. Take a multimeter, and match up the pins to the diagram on the relay. Check for continuity on the right pair of terminals. You can also connect twelve volts to the control pins and listen for a clicking sound. If you get a solid click and the tester shows it’s passing current across the right pins, the relay checks out. If not, it’s time for a replacement.
Can I Bypass The Mercedes E420 Fuel Pump Relay?
You can bypass the Mercedes E420 fuel pump relay temporarily for troubleshooting. Use a jumper wire to connect the power and output terminals in the relay socket. The fuel pump will run whenever the key is on. That helps to check if the problem is the relay versus the pump. Don’t leave the jumper in if you plan to drive, though—the relay protects the wiring and keeps everything safe, so replace it if it’s not working.
What Causes A Mercedes E420 Fuel Pump Relay To Fail?
The Mercedes E420 fuel pump relay fails for reasons that stack up over time. Heat from the engine and repeated cycles wear out the internal contacts inside the relay. Sometimes corrosion works in, or a fuel pump that draws too much electrical power fries the relay. Vibration, moisture, and even just old age can finish it off. When the relay gets tired, it can’t send steady power, so the pump won’t get what it needs.
Where Can You Find Affordable Mercedes E420 Fuel Pump Relays?
AutohausAZ keeps Mercedes E420 fuel pump relays in stock, priced right. Orders ship fast, and their return policy is simple if you need to swap out parts. With reliable service and fair pricing, you get what you need and get back on the road.
