The VW Passat Fuel Pump Relay Location: Find It Fast By Model Year & Generation

The exact location of the fuel pump relay in your Volkswagen Passat depends significantly on your specific model year and generation. For most Passats (B5, B5.5, B6, B7, B8), you will find it in the primary relay panel located under the dashboard on the driver's side (left-hand drive vehicles). It's typically secured to the underside of the dashboard fuse box cover or clipped onto the fuse box frame itself. The precise position within this panel and the relay number varies. Finding it requires checking your owner's manual fuse diagram or the lid of the fuse box.

That non-starting Passat – the engine cranking but refusing to catch – often points to an electrical issue. While a failed fuel pump is a common culprit, the component responsible for sending power to that pump, the fuel pump relay, is an equally likely suspect and generally much easier and cheaper to replace. Knowing where to find the VW Passat fuel pump relay is the critical first step in diagnosing and resolving this common problem.

The Under-Dash Relay Panel: Your Primary Target

For the vast majority of Volkswagen Passat models across several generations, the central electronic control module (often called the "onboard supply control unit" or just the "relay panel") lives under the dashboard on the driver's side. This applies to left-hand drive vehicles; for right-hand drive markets (like the UK, Australia, Japan), it will be under the dashboard on the passenger side. This panel houses numerous fuses and relays responsible for critical vehicle functions, including those related to fuel delivery, engine management, and interior electronics.

  • Accessing the Panel: You typically gain access by:

    1. Opening the driver's door.
    2. Looking for a plastic panel or cover running along the side of the dashboard, perpendicular to the door. This is lower than the primary knee bolster trim.
    3. Removing any fasteners securing this panel (often just plastic clips or small screws). Sometimes, carefully prying the edge near the door opening releases clips holding it in place.
    4. Gently pulling the panel straight down or slightly outward to unhook it. You don't usually need to remove the entire lower knee bolster unless specified in your manual.

  • Identifying the Fuel Pump Relay: Once the panel is removed, you'll see a fuse box frame, often black plastic. The fuel pump relay will be plugged into this frame, along with several other identical or similar looking relays. This is where knowing your specific relay position or number is crucial.

Generation-Specific Locations (Common Layouts)

While the under-dash panel is the home base, the fuel pump relay's exact position within that panel varies. Here's a breakdown of the most common setups based on widespread user and service information:

  1. B5 (1998-2001 North America / 1996-2001 Europe) & B5.5 (2001.5-2005 North America / 2001-2005 Europe):

    • Relay Panel: Under driver's dash (LHD).
    • Common Relay Numbers: 167, 109, or sometimes 372 or 373.
    • Typical Position: Often located at position 12 in the relay panel frame. Crucially, it is frequently physically attached to the underside of the plastic fuse box access cover you just removed. Flip the cover over! You should see several relays clipped directly onto it. It might also be directly on the frame itself near position 12. Check both places if not immediately obvious.
    • Description: Look for a standard gray or black 4-prong or 5-prong relay. It will be labeled with its number (167, 109, etc.).

  2. B6 (2006-2010 North America / 2005-2010 Europe) & B7 (2011-2015 North America / 2010-2015 Europe):

    • Relay Panel: Under driver's dash (LHD).
    • Common Relay Numbers: 167, 100 (often for fuse panel main supply, related), 645 (sometimes used), 645 (Engine Component Power Supply Relay - J757 - which controls power to multiple components including the fuel pump control module). J17 is the standard VW designation for the fuel pump relay.
    • Typical Position: Position 4, 7, 8, 10, or 11 are frequently cited locations for the fuel pump relay/J17/645. Like the B5, check carefully the underside of the fuse box cover you removed. The fuel pump relay is VERY commonly clipped right to this cover. Failing that, check these numbered positions on the frame. Positions vary significantly year-by-year and market-by-market.
    • Description: Again, a standard-looking relay (gray, black, beige, often 4 or 5 prongs) labeled with its specific number. Don't rely solely on color or size.

  3. B8 (2015-Present North America / 2015-Present Europe):

    • Relay Panel: Under driver's dash (LHD) remains the primary location.
    • Important Change: The B8 generation saw a significant evolution in VW's electrical architecture. While relays still exist for some functions, control is increasingly centralized into higher-power "fuse holders" or dedicated control units.
    • Fuel Pump Control: On most B8 Passats, especially those with direct injection (TSI) engines, fuel pump operation is primarily managed by the Fuel Pump Control Module (FPCM) (J538). This is a more complex electronic module, not a simple relay.
    • Relay Presence (Sometimes): There may still be a smaller relay triggering the FPCM itself. This relay (often designated for the FPCM) might reside under the dash OR sometimes in the engine bay fuse box (positions vary widely - 6, 10, SC37 referenced sometimes for FPCM supply).
    • Key Takeaway: For B8, finding a simple "fuel pump relay" is less common. Diagnosis often requires checking fuses related to the FPCM (located in both the under-dash and engine bay fuse boxes) and potentially scanning for fault codes pointing to J538 failure. Consult a specific wiring diagram or manual for your exact B8 model year.

The Critical Reference: Your Fuse Diagram

The single most important tool for locating the exact relay in your specific Passat is the fuse and relay diagram. Manufacturers design these for a reason:

  1. Located On Fuse Box Cover/Lid: Carefully remove the panel cover you took off to access the relay panel. Both the underside of this cover and its top surface usually have detailed diagrams printed or molded into the plastic.
  2. Found In Your Owner's Manual: Your vehicle's manual contains a specific diagram listing every fuse and relay position, including their numbers, amperage ratings, and the circuits they protect/supply power to.
  3. Diagram Layout: These diagrams use a clear grid system corresponding to the physical layout inside the fuse box. Each relay position is numbered (e.g., Position 1, Position 2, etc.). The diagram will list, for each numbered position, what the relay is for. Look for entries like:
    • Fuel Pump Relay (J17)
    • Relay for Fuel Pump (167)
    • Motronic Power Supply Relay (J271) (sometimes powers the ECU, which then activates the pump)
    • Engine Components Power Supply Relay (J757) or Load Reduction Relay
    • Pre-Fuel Pump Relay
    • FPCM Control Relay (B8)

Identifying the Relay Itself

Once you locate the position indicated by the diagram for the fuel pump circuit, you need to be sure you're pulling the correct physical component:

  • Standard Automotive Relay: It will typically be a small cube (roughly 1 inch x 1 inch x 1.5 inches) made of plastic (gray, black, beige, white). Avoid touching round or metallic components – those are typically fuses or resistor packs.
  • Relay Number: Crucially, the relay itself has its number molded into the plastic casing (167, 109, 645, J17, J757, etc.). Match this number to the number shown on your fuse diagram for the fuel pump circuit.
  • Position: Double-check that the position number on the fuse panel frame aligns with the position listed in the diagram for the fuel pump relay. Position 12 on the frame should correspond to the component listed in the diagram for Position 12.
  • Color Coding (Less Reliable): While some relays share similar colors, never rely solely on color for identification. The molded number is definitive.

How to Test a Suspect Fuel Pump Relay (Simplified)

Replacing the relay is inexpensive and often the first step before suspecting the fuel pump itself. A simple test:

  1. Locate It: Use the diagram to find the correct relay position and pull out the relay identified as controlling the fuel pump.
  2. The "Click" Test (Simple):
    • Have an assistant turn the ignition key to the "ON" position (don't start the engine).
    • Place your fingers firmly on the relay. You should feel and usually hear a distinct click within 1-2 seconds of turning the key to "ON". This click indicates the relay coil is energizing and the internal switch is closing.
    • If you don't feel/hear the click, it strongly suggests the relay coil circuit isn't working (failed relay, fuse, wiring, ECU signal).
  3. Swap Test (Most Common/Practical):
    • Find another relay in the same fuse panel that has the identical part number molded onto it (e.g., swap one 167 for another 167).
    • Common donor relays include those for the horn, headlights (high or low beam), or fan control – ONLY swap if the numbers match exactly!
    • Place the known good relay into the fuel pump relay socket. Turn the ignition to "ON". Listen carefully near the fuel tank filler area – you should hear the fuel pump whine for 2-3 seconds as it primes the system. If it whines now when it didn't before, your original relay is faulty.
    • Alternatively, attempt to start the car. If it starts with the swapped relay, the original fuel pump relay is bad.
  4. Visual Inspection: While less conclusive, inspect the relay's electrical contacts for any signs of burning, corrosion, or melting. These are visual indicators of failure.

Replacing a Faulty Fuel Pump Relay

  1. Identify Correct Replacement: Take the old relay to an auto parts store. Match the exact part number molded on it. Relays are inexpensive.
  2. Disconnect Battery (Recommended): While you can often swap relays with the battery connected, disconnecting the negative terminal eliminates any risk of short circuits or triggering fault codes. Leave the key out of the ignition.
  3. Access & Remove: Access the under-dash panel as described earlier. Locate the correct relay using the diagram. To remove, pull it straight out from its socket. Wiggle gently if stuck but avoid excessive force.
  4. Install: Orient the new relay correctly (match the pin configuration) and push it firmly into the socket until it clicks and is fully seated. Don't force it – if it doesn't slide in easily, it might be oriented incorrectly.
  5. Reconnect & Test: Reconnect the battery (if disconnected). Turn the ignition to "ON" and listen for the pump prime. Attempt to start the engine.

Crucial Troubleshooting Considerations

  1. Not Starting? Could Still Be Other Issues: While a clicking relay during the test or a successful start after swap points firmly to the relay, its failure doesn't guarantee the fuel pump is good. If the car runs with a new relay, great. If not, fuel pump diagnosis is the next step. A failed relay can also cause intermittent problems or stalling.
  2. Fuses: Always check relevant fuses first and after replacing a relay. The fuse powering the relay coil circuit or the fuel pump circuit could blow, causing the relay not to click. A blown fuse can also occur at the same time as a relay failure or immediately after replacing a relay if a downstream problem (like a failing pump causing a short) exists. Check fuses in both under-dash and engine bay boxes (as per your diagram).
  3. Inertia Switch (Less Common): Some Passats have a fuel pump inertia switch that cuts power to the pump in the event of an impact. It can sometimes trip inadvertently and needs a reset button pressed. Check your owner's manual for its location (sometimes in the trunk area or under dash/passenger carpet).
  4. Relay Socket: Inspect the socket where the relay plugs in. Look for any bent pins, corrosion, or signs of overheating/melting. Damaged sockets can prevent a new relay from working and require repair.
  5. Wiring Issues: Damaged wires between the relay, fuel pump, fuse box, or ECU can mimic relay or pump failure. This is less common but becomes more likely if replacing the relay and checking fuses/pump doesn't resolve the issue. Requires more advanced diagnosis.
  6. FPCM Failure (B8): On newer B8 Passats, a failure of the Fuel Pump Control Module itself (J538) is a known cause. It often throws specific fault codes (like P310B).

Why Knowing the Location Matters

The fuel pump relay is a prime example of a component where a 30 part and 15 minutes of your time can resolve a problem that might otherwise require expensive diagnostics and potentially hundreds of dollars replacing the actual fuel pump unnecessarily. Finding its location – specific to your Passat's model year – empowers you to perform a critical diagnostic step quickly and economically. The under-dash panel is the hunting ground; the fuse/relay diagram is your indispensable map. Always start there, verify with the number on the relay, test, and replace if faulty before pursuing more complex or costly repairs.

Back to blog