1999 Nissan Sentra Fuel Pump Relay Location: A Complete Guide for DIY Diagnosis and Repair

Here is the bottom line: On a 1999 Nissan Sentra, the fuel pump relay is located behind the left side of the dashboard, near the fuse block on the driver's side. Wiring diagrams for the 1999 Sentra confirm that the fuel pump relay is positioned "behind left side of dash" . This is the most common location for the 1.6L GA16DE engine, which is the standard engine for most 1999 Sentra models in North America. The relay itself is a small, cube-shaped component that controls power delivery to the fuel pump inside the gas tank. Knowing exactly where to find it and how to test it can save you hours of frustration and unnecessary expense.

Understanding the Fuel Pump Relay in Your 1999 Sentra

The fuel pump relay is an electrical switch that controls when the fuel pump receives power. When you turn the ignition key to the "ON" position, the relay closes and sends power to the fuel pump, which then pressurizes the fuel system for about two to three seconds . This priming sound is a faint whirring noise you can hear from the rear of the car near the fuel tank. If you do not hear this sound, the relay, the fuel pump fuse, or the pump itself may be the problem .

The 1999 Nissan Sentra is equipped with a fuel pump relay . It is a standard component in the vehicle's electrical system and is not something that can be bypassed or removed without causing the engine to fail to start. The relay is part of the engine control system, and it works alongside the fuel pump fuse located in the interior fuse panel .

Where to Look: The Exact Location of the Fuel Pump Relay

For the 1999 Nissan Sentra, the fuel pump relay is located in two possible areas depending on the specific market and trim level, but the most reliable location is behind the dashboard.

Location 1: Behind the Dashboard (Driver's Side)
This is the primary location for the 1999 Sentra with the 1.6L engine . Here is how to access it:

  • Sit in the driver's seat and look under the dashboard on the left side, near the steering column.
  • You will see a fuse block attached to a bracket. The fuel pump relay is mounted on or near this fuse block.
  • You may need to use a flashlight to see clearly because the relay is often tucked away behind wiring and other components.
  • The relay is a small, rectangular box that plugs into a socket. It is usually green, blue, or brown in color .

Location 2: Under the Hood (Engine Bay Fuse Box)
Some 1999 Sentra models, particularly those with different engine configurations or sold in specific markets, have the fuel pump relay located in the engine compartment fuse box . To check this location:

  • Open the hood and locate the fuse box near the battery .
  • Remove the cover of the fuse box. The inside of the cover usually has a diagram showing the position of each relay and fuse.
  • Look for a relay labeled "Fuel Pump" or "FP" .

Important Note: If you have a 1999 Sentra with the 2.0L SR20DE engine, the wiring diagrams also show the fuel pump relay behind the left side of the dash, so this location is consistent across both engine options .

How to Identify the Fuel Pump Relay

Once you are looking at the relay cluster, you need to identify the correct one. Here are some tips:

Check the Labeling
The relay socket or the relay itself should be labeled. Look for markings like "Fuel Pump," "FP," or a symbol that looks like a gas pump . The fuse box diagram on the cover is your best friend here.

Look at the Color
While the color is not a guarantee, the fuel pump relay on a 1999 Nissan Sentra is often a different color than the other relays. Common colors include green, blue, or brown . However, do not rely solely on color because Nissan changed relay colors over production years.

Trace the Wiring
If you are still unsure, trace the wiring from the fuel pump relay socket. The wires should lead to the fuel pump circuit. You can also check the wiring diagram in your vehicle's service manual .

Swapping Test
A quick way to test if a relay is working is to swap it with another relay of the same type, such as the horn relay or the air conditioning relay . If the fuel pump starts working after swapping, the original relay is faulty.

Before You Replace the Relay: Check the Fuse

Before you spend money on a new relay, check the fuel pump fuse. The fuel pump fuse is much easier to access and is a common cause of no-start conditions.

Location of the Fuel Pump Fuse
The fuel pump fuse for the 1999 Nissan Sentra is located in the interior fuse panel, behind the dashboard on the driver's side. It is fuse number 17, and it is a 15-amp fuse . The fuse box is located near the hood release panel .

How to Check the Fuse

  1. Open the driver's side door and look at the end of the dashboard near the door hinge.
  2. Pull the cover off the fuse panel.
  3. Locate fuse number 17 (15A) using the diagram on the cover.
  4. Pull the fuse out and look at the metal strip inside. If it is broken or melted, the fuse is blown .
  5. Replace the fuse with a new 15-amp fuse. If the new fuse blows immediately, you have a short circuit in the wiring somewhere .

Testing the Fuel Pump Relay Yourself

If the fuse is good and you suspect the relay is the problem, you can test it with a multimeter. Here is a simple method:

What You Need

  • A digital multimeter (volt meter)
  • A helper (optional but helpful)
  • A spare relay (optional for swapping)

Step-by-Step Test

  1. Locate the relay: Gain access to the fuel pump relay behind the dashboard or under the hood.
  2. Remove the relay: Gently pull the relay straight out of its socket.
  3. Identify the terminals: Look at the relay base. It typically has four or five terminals numbered 1, 2, 3, 4, and sometimes 5. You need to identify the coil terminals (usually 1 and 2) and the switch terminals (usually 3 and 4).
  4. Apply power: Connect a 12-volt battery source to terminal 1 and a ground to terminal 2. You should hear a distinct "click" sound if the relay coil is working .
  5. Check continuity: With the relay powered, use your multimeter to check for continuity between terminals 3 and 4. The meter should show a closed circuit (zero resistance). If you remove power, the circuit should open (infinite resistance).
  6. If no click: If the relay does not click when you apply power, the coil is burned out, and the relay is bad.
  7. If no continuity: If the relay clicks but the switch terminals do not show continuity, the internal contacts are damaged, and the relay is bad.

Common Symptoms of a Faulty Fuel Pump Relay

If your fuel pump relay is failing, you will likely notice one or more of these symptoms :

No Start Condition
The engine cranks over normally when you turn the key, but it does not start. You may also notice that you do not hear the fuel pump priming sound when you turn the key to the "ON" position . This is the most common symptom.

Intermittent Stalling
The car runs fine for a while, then suddenly the engine cuts out while you are driving. After a few minutes, it may start again. This happens because the relay's internal contacts are worn and intermittently lose connection .

Engine Sputtering or Hesitation
If the relay is partially failing, it may not supply full voltage to the fuel pump. This can cause the engine to sputter, hesitate, or lose power, especially under acceleration or when climbing hills .

Reduced Fuel Pressure
A faulty relay can cause the fuel pump to run at a lower voltage than needed. This results in lower fuel pressure, which can cause the engine to run lean. You can test this with a fuel pressure gauge. The correct pressure for a 1999 Sentra is around 43 PSI .

Replacing the Fuel Pump Relay: A Simple DIY Job

Replacing the fuel pump relay is one of the easiest repairs you can do on your 1999 Nissan Sentra. It takes about five minutes and requires no special tools.

What You Need

  • A new fuel pump relay (Nissan OEM or a high-quality aftermarket relay)
  • A flashlight (if you are working behind the dashboard)
  • A small flathead screwdriver (optional, to help pry the relay out)

Step-by-Step Replacement

  1. Turn off the engine: Make sure the ignition is off and the key is removed from the steering column .
  2. Locate the relay: Find the fuel pump relay behind the left side of the dashboard or in the engine bay fuse box, depending on your vehicle.
  3. Remove the old relay: Grasp the relay firmly and pull it straight out of its socket. If it is tight, you can use a small flathead screwdriver to gently pry it out.
  4. Install the new relay: Align the new relay with the socket (the shape is usually keyed so it only fits one way) and push it firmly into place until it clicks.
  5. Test the repair: Turn the ignition key to the "ON" position and listen for the fuel pump priming sound. If you hear it, the repair is successful. Start the engine to confirm.

When the Relay Is Not the Problem: Other Fuel System Issues

If you replace the fuel pump relay and the car still does not start, the problem may be elsewhere in the fuel system. Here are other common causes:

Clogged Fuel Filter
A clogged fuel filter can restrict fuel flow to the engine, causing symptoms similar to a bad fuel pump. The fuel filter on the 1999 Sentra is located along the fuel line under the vehicle. Replacing it is a good idea if you are unsure of its age.

Bad Fuel Pump
If the relay and fuse are both good, the fuel pump itself may have failed. The fuel pump is located inside the fuel tank and is accessed through a panel under the rear seat . Before replacing the pump, you can test it with a fuel pressure gauge to confirm it is not delivering enough pressure .

Corroded Wiring or Connections
Corrosion on the wiring harness near the fuel tank or at the relay socket can disrupt the electrical circuit. Look for green residue or frayed wires and clean or replace them as needed .

Blown Fuel Pump Fuse
As mentioned earlier, check the 15-amp fuel pump fuse (fuse number 17) in the interior fuse panel. If it is blown, replace it and see if the car starts .

Recommended Fuel Pump Upgrade: KEMSO Fuel Pump

If you have determined that the fuel pump itself needs replacement, or if you want to upgrade to a more reliable and high-performance component, we highly recommend the KEMSO brand Fuel Pump. KEMSO fuel pumps are designed to be a direct OEM replacement for your 1999 Nissan Sentra, meaning they fit perfectly and work just like the original part.

Why Choose KEMSO?
KEMSO fuel pumps are built with high-performance standards to ensure your engine receives a consistent and reliable fuel supply. Whether you are dealing with a daily driver or a project car, a KEMSO pump delivers the flow and pressure your Sentra needs.

Lifetime Warranty
One of the best features of a KEMSO fuel pump is the lifetime warranty. This means you can install the pump with confidence, knowing that it is backed by a promise of durability and quality. If anything goes wrong, you are covered.

Visit the KEMSO Website
To see the full range of fuel pumps available for your 1999 Nissan Sentra and many other vehicles, visit the official KEMSO website at:
https://www.kemsoracing.com/

Final Thoughts on the 1999 Nissan Sentra Fuel Pump Relay

Finding the fuel pump relay on a 1999 Nissan Sentra is a straightforward task once you know where to look. The relay is located behind the left side of the dashboard near the fuse block . Before you panic and assume the entire fuel pump is bad, always check the relay and the fuse first. A blown fuse or a faulty relay is a simple and cheap fix compared to replacing the fuel pump inside the tank.

If you are still experiencing issues after checking the relay and the fuse, move on to testing the fuel pump itself with a pressure gauge. A reading of 0 PSI indicates a lack of fuel delivery, and a reading below 43 PSI suggests a weak pump . In that case, replacing the pump with a high-quality unit like a KEMSO fuel pump is your best bet for long-term reliability.

Remember, patience and a good flashlight are your best tools when working behind the dashboard. Take your time, label any wires if you disconnect them, and always consult your vehicle's service manual for specific details about your particular trim level. With a little effort, you can get your 1999 Nissan Sentra back on the road without spending a fortune at a repair shop.

For more information on high-performance fuel pumps and to find the right part for your vehicle, be sure to visit https://www.kemsoracing.com/.


Back to blog