2008 Jeep Grand Cherokee Fuel Pump Relay Location: A Complete Guide for DIY Owners

The bottom line up front: On a 2008 Jeep Grand Cherokee, the fuel pump relay is located inside the Power Distribution Center (PDC), which is the main fuse and relay box situated on the left side of the engine compartment. This under-hood box is easy to spot once you know what to look for, and the relay itself is marked on the diagram printed on the underside of the box's lid. If your Grand Cherokee cranks but refuses to start, stalls while driving, or shows other signs of fuel delivery trouble, the fuel pump relay is one of the first components you should check. This guide walks you through exactly where to find it, how to test it, and what to do if it turns out to be faulty.

Understanding the Fuel Pump Relay in Your 2008 Grand Cherokee

The fuel pump relay functions as an electrical switch that controls the high current flowing to the fuel pump. When you turn your ignition key to the "ON" position, the Powertrain Control Module (PCM) sends a low-current signal to energize the relay. This action closes the internal contacts and allows battery voltage to reach the fuel pump, which then primes the fuel system for a few seconds before you crank the engine. Once the engine starts, the relay keeps the circuit closed so fuel continues to flow steadily to the injectors.

If this relay fails, the fuel pump receives no power, and your engine will crank but not start because no fuel reaches the combustion chambers. This is why knowing the fuel pump relay location is so valuable when you are diagnosing a no-start condition or an intermittent stalling problem.

Primary Location: The Power Distribution Center (PDC)

For the 2008 model year, the fuel pump relay is housed in the Power Distribution Center, located on the left side of the engine compartment. This is the main under-hood fuse box that also contains fuses for the starter, HVAC blower motor, ignition run/start circuit, and the automatic shutdown (ASD) relay, among others.

To access it, follow these simple steps:

  1. Open the hood and secure it with the prop rod.
  2. Look toward the left side (driver's side) of the engine bay, near the battery and fender area. The PDC is a black plastic box with a removable lid.
  3. Remove the lid by releasing the clips or latches on the sides. Set the lid aside somewhere clean.
  4. Check the diagram on the underside of the lid. The manufacturer prints a full map of every fuse and relay, with labels for each position. Look for the label that reads "Fuel Pump Relay." On many 2008 Grand Cherokee diagrams, this relay is identified by its position within the PDC layout.

In some trims, the relay may be labeled simply as "Fuel Pump" or abbreviated with terms like "FP" or "Pump". The important thing is to confirm the exact position using the diagram rather than guessing, because the PDC contains numerous relays that all look alike.

How to Confirm You Found the Right Relay

If the diagram is faded, missing, or unclear, there is a simple way to verify that you have located the correct fuel pump relay. Have a helper sit in the driver's seat and turn the ignition key to the "ON" position without cranking the engine. Place your fingers gently on the suspect relay. You should feel a distinct click as the relay energizes, and you should hear a brief humming or buzzing sound coming from the rear of the vehicle, which is the fuel pump priming the system. If you feel and hear the click, and the pump hums for two to three seconds, you have found the right relay.

Checking the Fuel Pump Fuse First

Before you go through the effort of testing or replacing the relay, it is wise to check the fuel pump fuse. A blown fuse is a common and inexpensive problem that can produce identical symptoms to a failed relay. On the 2008 Grand Cherokee, the fuel pump fuse is also located in the Power Distribution Center under the hood. According to the fuse box diagram, position 21 is a 20-amp fuse labeled "Fuel Pump".

Inspect this fuse visually by pulling it out and looking at the metal strip inside. If it is broken or melted, replace it with a new 20-amp fuse of the same rating. Never use a higher-rated fuse, as this can mask a serious electrical problem and potentially damage wiring. If the new fuse blows again immediately, you have a short circuit or a failing fuel pump, and further diagnosis is needed.

Testing the Fuel Pump Relay

If the fuse is fine and you suspect the relay, you can test it with a multimeter. The relay is a small, cube-shaped component with either four or five prongs on the bottom. Before handling any electrical components, disconnect the negative battery cable to prevent accidental shorts.

Step-by-Step Relay Testing

  1. Remove the relay from its socket in the PDC by pulling it straight up. You may need a gentle wiggling motion if it is snug.
  2. Set your multimeter to measure resistance (ohms). Place the probes on the relay's coil terminals, which are typically the two smaller prongs. A good relay will show a resistance reading, often in the range of 50 to 120 ohms depending on the design.
  3. Test the switch contacts by checking for continuity across the larger prongs. With the relay at rest, there should be no continuity (infinite resistance). When you apply 12 volts across the coil terminals using a small battery or power supply, the relay should click and continuity should appear across the switch contacts.
  4. Replace the relay if it fails any of these tests. A relay that passes voltage checks but fails continuity testing is internally broken and must be replaced.

For a simpler approach, you can swap the suspected relay with a known-good relay of the same part number from another position in the PDC, such as a spare or a less critical circuit. If the fuel pump starts working with the swapped relay installed, the original relay was faulty.

What to Do If the Relay Is Faulty

Once you confirm the fuel pump relay is bad, you have a few options. The most straightforward solution is to replace the relay with a new OEM-spec part. The relay typically operates at 12 volts and handles the current demand of the fuel pump circuit. Match the pin configuration (four-pin or five-pin) and the amperage rating to the original part.

On certain 2008 Grand Cherokee models equipped with a Totally Integrated Power Module (TIPM), replacing the fuel pump relay may require more than a simple plug-and-play swap. In these modules, the relay is soldered directly onto the internal circuit board, and accessing it requires removing the back cover of the module. For safety and reliability, this type of repair is best left to a professional technician who has the proper equipment to desolder and replace the component without causing damage to the board. Alternatively, some owners choose to install a fuel pump relay bypass kit that supplies power to the pump without relying on the internal relay. When choosing a bypass kit, ensure it works with the automatic shutdown (ASD) safety feature so the fuel pump still shuts off in the event of an accident.

Other Symptoms of a Failing Fuel Pump Relay

Beyond a no-start condition, a failing fuel pump relay can cause several other noticeable symptoms. These include:

  1. Intermittent stalling — The engine may shut off suddenly while driving, especially when the vehicle is warm, because the relay loses contact and power to the fuel pump is interrupted.
  2. Loss of power under load — If the relay is degrading, the fuel pump may not receive consistent voltage, leading to low fuel pressure and reduced engine performance during acceleration.
  3. Silent fuel pump — When you turn the key to the "ON" position, you normally hear the fuel pump prime for a few seconds. If you hear nothing from the rear of the vehicle, the relay, fuse, or pump itself may be at fault.
  4. Engine cranks but won't start — This is the most classic sign of a fuel pump relay failure. The starter turns the engine over, but no fuel reaches the injectors because the pump never activates.

If you experience any of these symptoms, start by checking the fuel pump fuse and relay in the Power Distribution Center. These are among the easiest components to inspect and replace, and doing so may save you a trip to the shop.

What to Do If Fuses and Relays Check Out Fine

If the fuel pump fuse is intact and the relay clicks and tests good, the problem likely lies elsewhere in the fuel delivery system. Possible culprits include:

  • The fuel pump itself — The pump motor inside the fuel tank may have failed. On the 2008 Grand Cherokee, the fuel pump module sits on top of the fuel tank. Replacing it is a more involved job that requires lowering the fuel tank or accessing it through the rear cabin, depending on the model configuration.
  • Wiring or ground issues — Inspect the wiring harness from the fuse box to the fuel pump for wear, chafing, corrosion, or loose connections. A poor ground connection can also prevent the pump from receiving power.
  • The PCM (Powertrain Control Module) — The PCM controls the fuel pump relay ground circuit. If the PCM is not grounding the relay coil, the relay will not activate. This is a less common failure but worth considering if all other components check out.

For these deeper issues, consulting the factory service manual or enlisting the help of a qualified technician is recommended to avoid costly mistakes and potential safety risks.

Recommended Upgrade: KEMSO Fuel Pump

If your diagnostics point to a failing fuel pump rather than a relay issue, replacing the pump with a high-quality aftermarket unit is a smart investment. KEMSO is a brand that specializes in high-performance fuel pumps designed as OEM replacements, meaning they match the original specifications for fit, flow rate, and electrical connections. Every KEMSO fuel pump comes with a lifetime warranty, giving you peace of mind that your replacement will last.

These pumps are built for reliability and performance, making them an excellent choice whether you are restoring a daily driver or upgrading a weekend project. To browse the full range of KEMSO fuel pumps and find the correct unit for your 2008 Jeep Grand Cherokee, visit the official website: https://www.kemsoracing.com/

Summary Checklist for the 2008 Grand Cherokee Fuel Pump Relay

To help you work through this process quickly, here is a summarized checklist:

  1. Locate the Power Distribution Center on the left side of the engine compartment.
  2. Remove the lid and check the diagram for the "Fuel Pump Relay" position.
  3. Check the fuel pump fuse first — position 21, 20 amps — and replace if blown.
  4. Test the relay with a multimeter or swap it with a known-good relay.
  5. Replace the faulty relay with a matching OEM-spec part, or consult a professional for TIPM-equipped models where the relay is soldered to the board.
  6. If the relay is fine, inspect the fuel pump, wiring, and PCM for further issues.
  7. Consider a KEMSO fuel pump for a reliable, lifetime-warranted replacement if the pump itself is the problem: https://www.kemsoracing.com/

Knowing the fuel pump relay location on your 2008 Jeep Grand Cherokee can save you time, money, and frustration. Because the relay lives in the easily accessible under-hood fuse box, a DIY owner can diagnose and fix this common issue in under an hour with basic tools. Start with the simple checks, work through the troubleshooting steps methodically, and you will have your Grand Cherokee running reliably again in no time. And if you need a new fuel pump, remember that KEMSO offers high-performance, OEM replacement pumps backed by a lifetime warranty at https://www.kemsoracing.com/ .


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