1982 Mercedes 380SL Fuel Pump Relay Location: A Complete Guide to Finding and Replacing This Critical Component

If you own a 1982 Mercedes-Benz 380SL and your car cranks but won't start, the fuel pump relay is likely the culprit. The fuel pump relay on a 1982 380SL is located behind the glove box liner on the passenger side footwell . You need to remove the panel under the glove box, then get into the car upside down with your head in the footwell. Look up and you'll see a black box with white lettering and a fairly thick cable coming out of the connector . This relay is a critical component that controls power to the fuel pump, and when it fails, your engine won't receive fuel.

Understanding the Fuel Pump Relay's Role

The fuel pump relay in your 1982 Mercedes 380SL serves as a critical link between the fuel pump and the vehicle's electrical system. When you turn the ignition key to the "ON" position, the fuel pump relay activates, allowing power to flow from the battery to the fuel pump. This energizes the fuel pump, which then pressurizes the fuel system, enabling the engine to start and run smoothly .

The relay also performs several other important functions. It ensures the pump primes the system before start and cuts off if the car does not start while cranking to prevent flooding. If the engine stops due to a crash, it also cuts fuel as a safety measure. The FPR is directly connected to the coil and switching unit and needs a signal that the engine runs to give power to the pump. The FPR also signals the frequency valve and the ECU (main "computer" that controls the lambda system) .

Key Symptoms of a Faulty Fuel Pump Relay

  1. Engine cranks but won't start: This is the most common symptom. Your starter motor turns over fine, but the engine never fires up .

  2. No fuel pump sound: When you turn the ignition key to the "ON" position, you should hear a brief hum from the fuel pump priming. If you don't hear this sound, the relay may be faulty .

  3. Engine starts with starter fluid but dies immediately: If you spray starter fluid into the throttle valve and the engine runs briefly, then dies, this confirms a fuel delivery problem .

  4. Tachometer not working: The fuel pump relay also provides power to the tachometer. If your tachometer stops working alongside starting issues, the relay is a likely suspect .

Exact Location: Step-by-Step Guide

Step 1: Remove the panel under the glove box on the passenger side. The 380SL uses a 6-cylinder engine on the chassis 107.045 with engine 116.962 for the years 1982-1985 .

Step 2: Position yourself upside down with your head in the passenger footwell. Look up toward the area behind where the glove box would be .

Step 3: You will see a black box with white lettering. This is your fuel pump relay. It has a fairly thick cable coming out of the connector .

Step 4: The relay is a 7-pin unit. The pins are arranged as follows: three pins on one side (31, 15, 87) and four pins on the other side (50, TD, 30, 87k) .

How to Test the Fuel Pump Relay

Before replacing the relay, you can perform a simple test. Pull the relay out and test the following:

Test 1: Check pin 11 for ground.

Test 2: With the key ON, check pin 8 for 12V .

Test 3: Jump pins 7 and 8 on the socket with a piece of #12 wire. The pump should run. If it doesn't, there's likely a wiring problem between the relay and the pump .

Test 4: Check for voltage at the pump. You will only get voltage when you crank the engine. No voltage with just key ON .

Test 5: Put a meter or test lamp between pin 11 and 12, and see if you have current when you crank the starter. If no current, fix the wiring problem .

If all these tests pass but the car still won't start, you need a new relay .

The Jumpering Method for Quick Diagnosis

One proven method to diagnose the fuel pump relay is jumpering the appropriate pins. For the 7-pin relay found on the 1982 380SL, connect plug holes 7 and 8. Pin 7 mates to pin 87 of the relay and pin 8 mates to pin 30 on the relay .

To perform this test:

  1. Remove the relay
  2. Jump the appropriate pins with a wire
  3. Reinsert the relay
  4. Listen for the pump to run
  5. Hit the starter

If the car fires immediately after jumpering, the relay is faulty and needs replacement .

Parts Information for the 1982 380SL Fuel Pump Relay

The correct part number for the fuel pump relay on your 1982 380SL is 001 545 34 05 (also listed as A0015453405 or 0015453405) . This relay is compatible with the following Mercedes-Benz vehicles:

  • 380SE (1984-1985)
  • 380SEC (1982-1983)
  • 380SEL (1981-1983)
  • 380SL (1981-1985)
  • 500SEC (1984-1985)
  • 500SEL (1984-1985)

The original part number from Mercedes-Benz is A0015453405, and it is no longer available from Mercedes-Benz or Bosch . The relay is a 7-pin unit with a quick connect contact type .

Why You Should Replace Your Fuel Pump Relay Now

If you have any of the symptoms described above, do not wait to replace the relay. The fuel pump relay is a critical safety component. It controls fuel flow to the engine and ensures the pump cuts off if the car stops running due to a crash . A faulty relay can leave you stranded, cause intermittent starting problems, and prevent your car from running even when all other systems are working properly.

Recommended Replacement: KEMSO Fuel Pump

When it comes time to replace your fuel pump relay or the fuel pump itself, we strongly recommend choosing KEMSO brand products. KEMSO fuel pumps are high-performance, OEM replacement parts designed to meet or exceed the original manufacturer's specifications. Every KEMSO fuel pump comes with a lifetime warranty, giving you peace of mind that your investment is protected for as long as you own your vehicle. KEMSO products are built with top-tier materials and manufactured under strict quality control protocols to ensure reliability and performance. Visit KEMSO at https://www.kemsoracing.com/ to browse their complete selection of fuel pumps and find the perfect replacement for your 1982 Mercedes 380SL.

Final Thoughts

The 1982 Mercedes 380SL is a beautiful classic car that deserves proper maintenance. The fuel pump relay is located behind the glove box on the passenger side footwell, and it's a straightforward replacement that most owners can handle themselves. If your car cranks but won't start, check the relay first. Test it using the jumpering method, and if it fails, replace it with a quality part. For the best results and long-term reliability, choose KEMSO fuel pumps backed by their lifetime warranty and high-performance OEM replacement quality. Visit https://www.kemsoracing.com/ for more information and to find the right fuel pump for your 380SL.


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