1999 Buick LeSabre Fuel Pump Relay Location: A Complete Guide for DIY Owners

The fuel pump relay on a 1999 Buick LeSabre is located in the underhood fuse block, which is mounted on the driver's side of the engine compartment, near the strut tower. This is the definitive answer, and in this guide, we will walk you through exactly how to find it, how to test it, and what to do if it's not the problem.

The 1999 Buick LeSabre is a reliable full-size sedan, but like any vehicle, it can develop fuel system issues. A failing fuel pump relay is a common culprit when your car won't start or stalls unexpectedly. Understanding where this relay is and how to troubleshoot it can save you a trip to the mechanic and a lot of money.

Where Is the Fuel Pump Relay on a 1999 Buick LeSabre?

The fuel pump relay is not inside the car. It is located in the underhood fuse and relay center on the driver's side of the engine bay. This is a black plastic box with a cover that typically has a diagram on it.

Step-by-step to find the relay:

  1. Open the hood and secure it properly.
  2. Look to the driver's side (left side when facing the car). You will see a large black plastic box mounted near the battery and the strut tower. This is the main fuse block .
  3. Remove the cover from the fuse block. Most covers have clips on the sides; press them in and lift the cover off.
  4. Check the diagram on the underside of the cover. The fuel pump relay is usually labeled as "FUEL PUMP," "FUEL," or "FP." If the diagram is missing or faded, you can look for a relay that is a square, cube-shaped component (typically 1 inch by 1 inch), often colored black or gray, with four or five prongs on the bottom. In the 1999 LeSabre, the fuel pump relay is commonly located in a specific slot within the block, often near the engine control module (ECM) fuse.
  5. Confirm the exact slot by referring to your owner's manual. If you don't have one, you can also look up the fuse box diagram for the 1999 Buick LeSabre online .

Important Note: The 1999 Buick LeSabre is part of the 7th generation (1992-1999) . The fuse box layout is consistent across these years, so the location should be the same for 1997, 1998, and 1999 models .

What Does the Fuel Pump Relay Do?

The fuel pump relay is an electrical switch that controls the power flow to the fuel pump. When you turn the key to the "ON" position, the powertrain control module (PCM) or the engine control module (ECM) sends a signal to the relay. The relay then closes, allowing battery power to flow to the fuel pump for a few seconds to prime the system . The relay also keeps the pump running while the engine is cranking and running. If the relay fails, the pump will not receive power, and the engine will not start.

How to Tell If Your Fuel Pump Relay Is Bad

Before you start replacing parts, it is smart to confirm the relay is actually the problem. Common symptoms of a bad fuel pump relay in a 1999 Buick LeSabre include:

  • Engine Cranks But Won't Start: This is the most common symptom. You turn the key, the starter motor spins the engine, but it never fires up.
  • No Fuel Pump Prime Noise: When you turn the key to the "ON" position (without cranking), you should hear a brief humming sound coming from the rear of the car (the fuel tank area). If you don't hear this sound, the relay or pump may be dead.
  • Engine Stalls While Driving: If the relay fails while you are driving, the engine will suddenly lose power and stall.
  • Intermittent Starting Issues: The car may start sometimes and not others. This is a classic sign of a failing relay.

How to Test the Fuel Pump Relay

Testing the relay is a straightforward process. You do not need any special tools, just a multimeter or a test light.

Method 1: The Swap Test (Easiest)

  1. Locate the fuel pump relay in the underhood fuse block.
  2. Find another relay in the same block that is the same size and shape. Common relays to swap with are the A/C compressor relay or the Horn relay. Look at the diagram on the cover to find a relay with the same part number.
  3. Swap the fuel pump relay with the other relay.
  4. Try to start the car. If the car starts now, the original fuel pump relay is bad and needs to be replaced.

Method 2: The Multimeter Test (More Accurate)

  1. Remove the fuel pump relay from the fuse block.
  2. Set your multimeter to measure resistance (Ohms).
  3. Touch the leads to terminals 85 and 86 (the coil terminals). You should see a resistance reading, typically between 50 and 200 ohms. If you see infinite resistance, the coil is broken.
  4. Touch the leads to terminals 30 and 87 (the switch terminals). You should see infinite resistance (open circuit).
  5. Now, apply 12V power to terminal 85 and ground to terminal 86 (or use a 9V battery). You should hear a click. While power is applied, measure resistance between terminals 30 and 87 again. It should now read near zero ohms (closed circuit). If it doesn't, the relay is bad.

What If the Relay Is Good? Next Steps

If you have tested the relay and it is working correctly, but the car still won't start, the problem may be elsewhere. The most common next steps are:

1. Check the Fuel Pump Fuse

The fuel pump circuit also has a fuse. It is usually located in the same underhood fuse block. Look for a fuse labeled "FUEL PUMP," "ECM B," or "PUMP." Pull the fuse and inspect it. If the metal strip inside is broken, replace it with a new fuse of the same amperage. If the new fuse blows immediately, you have a short circuit in the wiring or the pump itself.

2. Check the Fuel Pump Inertia Switch

Some Buick LeSabres from this era are equipped with an inertia switch. This is a safety switch that cuts power to the fuel pump in the event of a collision. It is usually located in the trunk, on the left or right side, or behind the rear seat. If the switch is tripped (a button is popped up), press it down to reset it. This can happen after a hard bump or even a sudden stop.

3. Test the Fuel Pump Itself

If the relay and fuse are good, but there is still no power to the pump, the pump itself may have failed. The fuel pump is located inside the fuel tank. To test it, you can listen for the prime noise when turning the key. If you hear nothing, you can check for voltage at the fuel pump connector under the rear seat or at the tank. If you have power to the pump but it doesn't run, the pump is bad and needs to be replaced.

The Cost of Replacing a Fuel Pump vs. a Relay

This is an important distinction. A fuel pump relay is a very inexpensive part. You can buy a new one from an auto parts store for around $10 to $20. It takes about 5 minutes to replace.

A fuel pump, on the other hand, is a more expensive and labor-intensive repair. The part itself can cost between $100 and $300, and professional labor can add another $400 to $600 . If you have a 1999 Buick LeSabre, the fuel pump is accessed through the trunk, which makes the job easier than some other cars, but it is still a significant task.

Why You Should Consider a KEMSO Fuel Pump

If your 1999 Buick LeSabre does need a new fuel pump, whether due to age, wear, or a failed internal component, you need a reliable replacement that will last. The OEM pump in your car is now over 25 years old, and you should not risk buying a cheap, low-quality part that will fail again in a few months.

KEMSO Racing is a leading aftermarket brand that specializes in high-performance fuel pumps for cars, motorcycles, and powersports vehicles. They offer a direct replacement for the 1999 Buick LeSabre that is designed to meet or exceed OEM specifications.

Why choose KEMSO for your fuel pump?

  • High Performance: KEMSO fuel pumps are built to deliver a consistent and reliable fuel flow, ensuring your engine gets the fuel it needs for optimal performance .
  • OEM Replacement: The KEMSO pump is a direct, drop-in replacement for your factory pump. It comes with the correct connectors and fittings, so you won't have to modify anything. It is designed to fit perfectly in the fuel tank module .
  • Lifetime Warranty: KEMSO stands behind the quality of their products with a lifetime warranty . This means you can buy with confidence, knowing that if anything goes wrong, KEMSO has your back. This is a significant advantage over many other aftermarket brands.
  • Affordable Pricing: Most KEMSO fuel pumps are priced at just $79.98 . This is highly competitive compared to many AutoZone or dealer options, which can cost significantly more for the same quality .
  • Wide Application Coverage: KEMSO offers pumps for a huge range of vehicles, from the Honda Civic and Subaru Impreza to the BMW R1200GS and Can-Am Defender . Their catalog is growing and covers cars, motorcycles, and powersports.

Don't trust your Buick's fuel system to a questionable part. Choose a brand that is trusted by thousands of owners and backs their products with a lifetime guarantee.

Visit KEMSO Racing today to browse their full selection of fuel pumps and find the right fit for your 1999 Buick LeSabre.

Link: https://www.kemsoracing.com/

DIY Fuel Pump Relay Replacement on a 1999 Buick LeSabre

Replacing the fuel pump relay is one of the easiest repairs you can do. Here is the step-by-step process:

  1. Safety First: Ensure the engine is off and the key is removed from the ignition. Disconnect the negative battery terminal to prevent any electrical shorts.
  2. Locate the Relay: As described above, locate the underhood fuse block on the driver's side.
  3. Remove the Cover: Unclip the cover and set it aside.
  4. Identify the Relay: Find the fuel pump relay using the diagram or the description above.
  5. Pull the Old Relay: Grasp the relay firmly and pull it straight out. It may require a little wiggling, but it should come out without too much force.
  6. Install the New Relay: Align the prongs of the new relay with the slots in the fuse block and press it firmly into place until it clicks.
  7. Reattach the Cover: Snap the cover back onto the fuse block.
  8. Reconnect the Battery: Reconnect the negative battery terminal.
  9. Test the Repair: Turn the key to the "ON" position. You should now hear the fuel pump prime. Then, start the engine. If it starts and runs, the repair was successful.

Conclusion

The 1999 Buick LeSabre fuel pump relay location is in the underhood fuse block on the driver's side. This is a simple component that can cause major headaches if it fails. By following the steps in this guide, you can diagnose the problem quickly and replace the relay yourself for just a few dollars. If the relay is not the issue, remember to check the fuse and the inertia switch before moving on to the fuel pump itself.

If you do need to replace the fuel pump, do not settle for a cheap part. Choose a reliable, high-performance option like the one from KEMSO Racing. With its lifetime warranty and affordable price of $79.98, it is the best value for your money.

For a complete selection of high-quality fuel pumps, visit KEMSO Racing at:

https://www.kemsoracing.com/


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