BMW E90 Fuel Pump Relay Location: Your Complete Guide

Knowing the precise location of the BMW E90 fuel pump relay is crucial when diagnosing fuel delivery issues like hard-starting, engine stalling, or complete no-start conditions. In all E90 models (sedan, touring, coupe, convertible, 2005-2013), the main electronic fuel pump relay is situated inside the glove compartment fuse panel, integrated within the Fuse and Relay Carrier (FRM) Box**. Its position varies slightly by model year and engine type, typically designated by slot number E (often K6310/K6300) or slot number K (often K6300).**

A malfunctioning fuel pump relay is a common culprit behind sudden breakdowns where the engine cranks but refuses to start due to a lack of fuel pressure. This relay acts as a critical electronic switch controlled by the engine control unit (ECU). When the driver turns the ignition key to start the position, the ECU sends a low-power signal to energize the relay coil. This action causes the relay's internal contacts to close, completing a high-power electrical circuit. This high-power circuit then delivers the necessary voltage from the vehicle's battery directly to the electric fuel pump located inside or near the fuel tank. The pump immediately begins pressurizing the fuel rail, supplying the fuel injectors with the pressurized gasoline needed for combustion. If this relay fails – either because its coil no longer energizes, its internal contacts become pitted and burned preventing current flow, or the physical relay develops an internal break – the crucial signal and power pathway to the fuel pump is interrupted. The pump remains silent, fuel pressure drops to zero, and while the starter may spin the engine vigorously (cranking), the absence of fuel means the engine cannot ignite and run. This specific symptom pattern – cranking but not starting, accompanied by no audible priming sound from the fuel tank area when the ignition is first turned on – strongly points toward a problem in the fuel pump circuit, with the relay being a prime suspect alongside the pump itself or its wiring. Identifying the relay's location is the essential first step in testing and resolving these potentially stranding failures quickly.

Glove Compartment Fuse Panel: Accessing the Main Fuel Pump Relay

The glove compartment fuse panel is the definitive home for the primary fuel pump relay controlling the main supply pump in the tank for gasoline E90 models. Finding it requires accessing the fuse box itself.

1. Preparing for Access: Begin by ensuring the vehicle is stationary with the ignition completely off. Remove the key or key fob from the ignition slot or ensure it is well away from the vehicle if equipped with Comfort Access. Engage the parking brake securely to prevent any unintended movement. Gather necessary tools: a plastic trim removal tool or a small flat-head screwdriver (used with extreme care to avoid scratches) is helpful, and having a flashlight ready significantly improves visibility within the confined glove box area.
2. Opening the Glove Box: Depress the glove box latch to open the compartment door fully. Some models feature a small Damper Strut on the right-hand side that gently lowers the box; simply allow it to open as far as possible.
3. Emptying the Glove Box: Remove all contents stored inside the glove box. Take out owner's manuals, documents, small items, or debris. A completely empty glove box prevents items from falling out during the next steps and allows clear access to the rear wall.
4. Locating the Fuse Box Cover: Look towards the rear interior surface of the open glove box compartment. You will find a large rectangular plastic cover, typically textured slightly differently than the surrounding glove box liner. This is the fuse box cover. It often has small indentations or finger grips along its bottom edge, and it might be secured by two or more plastic clips near its top edge.
5. Removing the Fuse Box Cover: Firmly grasp the cover along its lower edge using the provided finger grips or by carefully leveraging a trim tool. Apply pressure directly backward (away from the glove box interior) and slightly downward. The cover should detach from its retaining clips near the top first, then pivot downward. Set the cover aside carefully in a safe location where it won't get damaged.
6. Identifying Components Inside the Fuse Panel: With the cover removed, you now see the Fuse and Relay Carrier (FRC/Fuse box) board. This board houses numerous colored plastic fuses of different Amperage ratings (marked by numbers like 5, 7.5, 10, 15, 20, 25, 30) and several larger, typically black or occasionally gray, cube-shaped components – these are the relays. Fuses protect circuits from over-current situations by blowing a fusible link internally; relays are electromagnetic switches controlling higher-power devices like the fuel pump, radiator fan, or horn using a lower-power signal from a control module.
7. Locating the Fuel Pump Relay Slot: Focus on the large relays plugged directly into the fuse board slots. The exact position and designation slot number vary significantly depending on your E90's specific production year and engine type. Consult the Fuse Assignment Diagram. This critical diagram is physically printed on the underside of the fuse box cover you just removed. This is the most reliable source for your specific car. You are looking for the relay responsible for the "Fuel Pump" or "FP". Key potential locations found on various E90 models include:
   • Slot E: This is a very common location labeled for K6310 (Fuel Pump, Supply Pump) or sometimes K6300. This relay is usually physically larger than micro-relays and standard color-coded black.
   • Slot K: Another common designation, sometimes shown as K6300 (Fuel Pump). Location might be near the center or lower left area of the main relay block.
   • Other Slots: Less commonly, it might be labeled as Slot D, Slot F, Slot 7, or Slot 11 depending on model variant. Reliance on the diagram is non-negotiable.
8. Recognizing the Relay Visually: Once you've identified the correct slot using the diagram, locate the specific relay plugged into that slot on the fuse board itself. The main fuel pump relay (K6310/K6300) in the glove box is typically a standard-sized black plastic cube, often measuring roughly 1 inch square. It will have four or five metal blade terminals protruding from its bottom to plug into the fuse board socket. Crucially, it will have numerical markings directly on its plastic case confirming its identity – look for 61.36-8 376 469 or 61.36-8 376 473 or 61.36-8 376 469 or the crucial 61366915819 or the BMW part number 61369158819 or newer versions like 61369317775. Match the number on the relay to the designation in the slot diagram. There are several identical-looking relays nearby; the printed numbers are the only reliable way to distinguish them without the diagram. If in doubt, note the exact slot position you intend to check against the diagram.

The Trunk/Boot Fuse Panel: Additional Relay Location (Diesel & Some Variants)

While the glove compartment fuse box houses the primary fuel pump relay for gasoline E90 models, an additional fuse panel exists in the trunk or boot compartment. This location is relevant for specific scenarios:

1. Diesel Engine Models: BMW E90 vehicles equipped with diesel engines (like the 318d, 320d, 330d, 335d) utilize the Electric Fuel Supply Pump (EKP) control module instead of a simple relay to manage the high-pressure fuel supply pump. This more complex module is often located within the trunk fuse panel area, bolted to the fuse box bracket or nearby. Replacing this module requires significant diagnosis.
2. Fuel Pump Control Module: Some higher-performance or later model year gasoline E90s might incorporate a Fuel Pump Control Module (FPCM), a more advanced unit capable of modulating fuel pump speed beyond simple on/off control. This module is typically found in the rear trunk fuse panel vicinity. Check the trunk fuse box diagram for components labeled EKP or FPCM.
3. Accessing the Trunk Fuse Panel: To reach this panel:
   • Open the vehicle's trunk or boot lid fully.
   • Locate the carpeted trim panel covering the left-hand side of the trunk well (as you face the rear of the car). This is usually where the battery compartment is situated.
   • Remove any cargo, spare tire, or trunk floor mats covering the area.
   • Find the fasteners securing the side trim panel. These might be plastic expansion rivets, screws covered by small caps, or Velcro sections.
   • Carefully remove the fasteners using an appropriate tool (like pliers for rivets or a screwdriver). Start at the top or sides.
   • Gently pull the trim panel away to expose the underlying fuse box mounted on the bodywork near the vehicle's battery.
   • Locate the main cover of this fuse box. This cover usually snaps off similarly to the glove box fuse cover.
   • Underneath, find large black or gray cube-shaped relays. The diagram printed inside the cover (lift it out gently) is essential.
   • Search for designations related to the Fuel Pump (FP), Fuel Pump Supply (EKP), or specific module part numbers relevant to diesel engines. Remember, a simple relay here is less likely for a gasoline fuel pump; it's usually the EKP module itself.

Diagnosing a Faulty Fuel Pump Relay

Knowing the location is only half the battle; diagnosing a suspected faulty relay is the next critical step before replacement.

1. Critical Safety: Always disconnect the negative (-) terminal of the vehicle's lead-acid battery located in the trunk using the correct size wrench (usually 10mm). Wait at least one full minute after disconnecting to allow vehicle modules to power down completely and prevent accidental airbag deployment or electrical shorts. Disconnect the battery terminal only when the vehicle is parked in a safe location, ignition is off, and keys are removed.

2. Removing the Suspect Relay: After locating the correct relay in the glove compartment fuse box using its slot number and visual markings, carefully grasp its plastic body firmly between your thumb and index finger. Pull it straight upward, applying steady, even pressure directly away from the fuse board. Avoid twisting or rocking the relay, as this could damage the fragile plastic socket. It should release smoothly. Place the removed relay on a clean, stable, non-metallic work surface.

3. The Simple Swaps Test: This is the quickest initial diagnostic check possible without specialized tools. Identify another relay within the glove compartment fuse box that shares the exact same physical appearance and, critically, identical printed part numbers. Standard relay candidates often include:

   • Horn relay (labeled HORN)
   • Radiator fan relays (labeled FAN)
   • Rear window defogger/heating relay (labeled RHR)
   • Front power socket (cigarette lighter) relay (labeled SOCKET)
   • Air conditioning compressor relay (sometimes A/C or COMP)
   • Transmission control relay (automatic models, sometimes TCM)

   Carefully swap the suspected fuel pump relay with one of these identically numbered relays. Reconnect the battery negative terminal securely and tighten it properly. Turn the ignition key to the "Run" position (position two, just before starting, where the dashboard lights illuminate). Listen intently near the rear seats or above the fuel tank area for the distinctive two-second humming or whirring sound that indicates the fuel pump is priming and building pressure in the fuel rail. If the previously silent fuel pump now activates correctly, and crucially, if the component that previously had the known good relay (e.g., the horn) now stops working, this conclusively proves the original fuel pump relay installed in its designated slot has failed internally and requires replacement. If no other identical relay exists or swapping yields unclear results, proceed to further testing with a multimeter for confirmation.

4. Advanced Testing with a Multimeter: For definitive confirmation, using a multimeter provides concrete electrical evidence. You will test for both coil circuit functionality and contact continuity:

   • Identify Relay Terminal Functions: Flip the relay upside down to see its electrical connection blades/pins. Looking at the relay’s underside, identify the five pins. Standard automotive relays follow the numbering convention printed on the bottom:
     • Pin 85: Coil Ground (-)
     • Pin 86: Coil Power (+)
     • Pin 30: Common Power Input (high power source from fuse/battery)
     • Pin 87: Normally Open Contact Output (sends power to fuel pump when relay energized)
     • Pin 87a: Normally Closed Contact Output (often unused; ignore for fuel pump testing).
   • Testing the Relay Coil (Low-Current Side): Set your digital multimeter to measure resistance (Ohms mode, Ω symbol). Touch one meter probe firmly to pin 85 and the other probe to pin 86. A functioning relay coil should show a resistance value typically between 60 and 100 Ohms. Refer to your specific relay part number specifications if possible. A reading of infinite resistance (OL) indicates a broken coil wire – the relay is bad. A reading of zero Ohms indicates a shorted coil – the relay is bad.
   • Testing the Contact Circuit (High-Current Side): Set your multimeter to Continuity Test mode (usually indicated by a diode symbol or sound wave icon; it beeps when a circuit is complete). Touch one probe to Pin 30 and the other probe to Pin 87. Without applying power to the coil pins (85/86), the meter should display infinite resistance or "OL," with no audible continuity beep – this verifies the contacts are open (normal state). Next, apply constant power from the vehicle battery to the coil terminals: Connect the positive (+) battery terminal lead using a fused jumper wire or suitable connector directly to relay pin 86. Connect the negative (-) battery terminal lead securely to relay pin 85. You should feel and hear an audible "click" as the relay energizes. With power applied to pins 85 and 86, retest the path between Pin 30 and Pin 87 using your continuity meter. Now, the meter should indicate a continuous circuit (near zero resistance) with a clear beep. This confirms the relay's internal switch mechanism is closing correctly to conduct current. Any failure to close the circuit or failure to achieve a solid connection proves contact failure within the relay. If the coil tests okay but the contacts fail either the open-circuit or closed-circuit test, the relay must be replaced.

5. Checking Fuse Connections: While the relay is a primary suspect, always verify the condition of related fuses located in the same glove compartment fuse panel. Use the fuse diagram printed under the cover to identify the fuse associated with the fuel pump circuit (common positions include Fuse 54 (30 Amp) or Fuse 57 (20 Amp), but always confirm using the diagram). Use the fuse puller tool often stored inside the fuse box cover. Visually inspect the thin metal fuse element inside the transparent plastic housing for any break. Check continuity with your multimeter if the element appears intact but failure is suspected. Replace any blown fuse only with one of the identical Amperage rating. Check the relay socket for corrosion or bent pins that might cause intermittent problems.

Symptoms Pointing to a Failed Fuel Pump Relay

Recognizing the symptoms helps pinpoint whether the fuel pump relay deserves investigation:

1. Failure to Start: The most definitive symptom. The engine cranks repeatedly with the starter motor turning vigorously, but the engine does not fire or run. This occurs because the ignition system and starter receive power normally, but the fuel pump receives no power to deliver gasoline to the engine cylinders.
2. No Fuel Pump Priming Sound: Upon turning the ignition to the "Run" position (before starting/cranking), listen carefully near the rear of the vehicle (around the back seats or directly over the fuel tank under the trunk floor). A healthy fuel pump generates a noticeable humming or whirring noise lasting 1-3 seconds as it pressurizes the fuel lines for starting. Complete silence strongly indicates the pump isn't receiving its required 12-volt power signal. This sound is the most common clue preceding complete failure.
3. Stalling During Operation: Intermittent relay failure can cause unexpected engine shutdowns while driving. The engine might sputter, lose power abruptly, or simply cut out as if the ignition were switched off. This often happens when vibration or temperature changes affect a failing relay internally.
4. Intermittent Starting Issues: The vehicle might start reliably sometimes but fail to start other times, with symptoms mirroring a dead battery (cranking) except the cranking itself is strong. This unpredictability is classic for failing electrical components like relays or wiring harness issues.
5. Complete Power Loss to Fuel Pump: Verifiable with a voltmeter at the fuel pump electrical connector in the tank access panel. More advanced diagnostics involve reading fuel pressure via diagnostic port with a scan tool (should show near zero PSI/bar if pump isn't running).

Replacing the BMW E90 Fuel Pump Relay

If diagnosis confirms the fuel pump relay is faulty, replacing it is generally straightforward:

1. Critical Safety: Disconnect the negative battery terminal as described previously.
2. Obtain the Correct Replacement Part: Purchase a relay specified for your E90. Never rely solely on physical appearance. Provide sellers with your VIN or specify:
   • Production Year
   • Engine Type (e.g., N52, N54, M57)
   • Chassis Type (E90, E91, E92, E93)
   • Original BMW Part Number found on the failed relay or in the fuse box diagram (e.g., 61369158819, 61369317775). An exact replacement part number match is essential.
   • Ensure you are buying the relay for the glove compartment location. Purchase from BMW dealerships, reputable auto parts stores (like Bosch, Hella), or established online retailers. Avoid generic or unknown brands.
3. Remove the Old Relay: Carefully pull the faulty relay straight out of its designated slot in the fuse panel as described earlier. Avoid excessive force.
4. Install the New Relay: Examine the pin arrangement on the bottom of the new relay. Orient it correctly by matching the pin pattern to the slot pattern in the fuse board socket. Firmly press the relay straight down into the socket until it seats completely and you feel it click into place securely. Do not force it; it should align correctly. A slight gap between the relay body and the fuse board surface is normal.
5. Reconnect Battery: Securely reconnect the negative battery terminal previously removed. Tighten the clamp bolt firmly to ensure good electrical contact. Close the hood and trunk properly.
6. Final Check: Turn the ignition key to "Run." Listen carefully for the fuel pump activation hum. If present, attempt to start the engine. A smooth start confirms the repair. If the issue persists, a deeper investigation into wiring harnesses, the fuel pump itself, or the ECU is necessary. Retest using methods described earlier.

Common Confusions Related to E90 Fuel Pump Location

Searching for the fuel pump relay location often leads to confusion with other components:

1. Electric Fuel Pump vs. Relay: The fuel pump relay is an electromagnetic switch located in the fuse panel area. The electric fuel pump is a powerful motor submerged inside the vehicle's fuel tank. The pump itself is accessed through an inspection hatch under the rear seat cushions or directly under the trunk liner near the spare wheel well. Replacing the pump requires removing seats or trunk liners. The relay controls the power reaching the pump motor.
2. Fuel Pump Control Module (FPCM/EKP): Primarily found on diesel models and some gasoline models like performance variants, the FPCM (Fuel Pump Control Module) or EKP (Elektrisches Kraftstoffpumpen-Steuergerät) is an electronic module located in the trunk fuse box area. It controls the pump speed. Diagnosing this requires professional tools like ISTA/D and isn't a simple relay swap.
3. Fuel Filter: An unrelated component often found underneath the vehicle along the fuel line path. It contains a replaceable filter element to clean debris from gasoline or diesel fuel before reaching the injectors. It requires no electrical connection and is replaced periodically as routine maintenance. Locate it under the vehicle near the tank or engine bay, depending on the model. Disconnect fuel lines and replace the filter element assembly as per maintenance schedules.
4. High-Pressure Fuel Pump (HPFP): Gasoline turbo engines (N54, N55, S55) utilize an additional high-pressure pump driven mechanically by the engine camshaft to generate the extreme pressure needed for direct injection systems. It mounts directly on the engine cylinder head. Its failure causes drivability problems but is unrelated to the low-pressure fuel tank pump controlled by the glove compartment relay. Diagnose HPFP issues using specific misfire codes and pressure data readouts via diagnostic tools.

When Professional Help is Necessary

While relay replacement is achievable for DIY enthusiasts, complex scenarios require workshop diagnosis:

1. Relay Replacement Didn't Fix the Problem: If symptoms persist despite installing a confirmed-working new relay, the underlying issue lies deeper – potentially the fuel pump motor itself, extensive wiring damage, connector issues, a blown fuse requiring replacement beyond just the relay, or an Engine Control Unit (ECU) malfunction preventing the relay activation signal.
2. Complex Module Failures: Diagnosing and replacing components like the Fuel Pump Control Module (FPCM), Electric Fuel Supply Pump module (EKP), or High-Pressure Fuel Pump (HPFP) requires specialized scanning equipment (BMW ISTA/D is standard) and advanced technical skills. Programming or adaptation procedures may be mandatory for new modules.
3. Extensive Wiring Harness Damage: Rodent damage to wiring, corrosion affecting connectors, impact damage crushing wiring conduits under the vehicle, or aging causing internal wire breaks necessitate detailed electrical testing beyond simple relay checks.
4. ECU Communication Problems: If the Engine Control Module fails to send the "turn on" signal to the relay when the ignition reaches the "Start" position or malfunctions internally, sophisticated diagnostics are necessary to isolate whether the ECU or its triggering inputs (e.g., immobilizer signal) are faulty.
5. Lack of Diagnostic Equipment: Basic multimeter testing can check relay function and fuse continuity but cannot retrieve trouble codes stored in the vehicle's computer systems, monitor live fuel pressure data, test module communications, or perform ECU resets and adaptations essential after certain repairs. Accessing these diagnostic capabilities requires specialized tools like advanced OBD-II scanners capable of BMW-specific protocols.

Conclusion: Confidence Starts with Knowing the Location

Pinpointing the BMW E90 fuel pump relay location – primarily inside the glove compartment fuse panel, typically in slots like E or K, with a secondary module location in the trunk fuse panel for diesel models – is fundamental knowledge for addressing fuel delivery no-start problems. Armed with your specific fuse box diagram to identify the relay's exact slot and part number, performing basic diagnosis like the simple swap test provides a fast path toward understanding whether this critical relay is the root cause. Understanding the distinct symptoms – engine cranking but not starting coupled with the absence of the fuel pump priming sound – immediately guides your focus toward the fuel pump circuit. Replacing a defective relay is a manageable task for most owners equipped with the right information and necessary safety precautions regarding battery disconnection. However, unresolved problems despite a good relay installation signal deeper electrical or mechanical faults requiring professional diagnostic procedures and repair techniques. Knowing where the relay resides empowers E90 owners to take the first informed steps toward resolving frustrating starting failures effectively.