1990 Corvette Fuel Pump Relay Location: A Complete Guide

The fuel pump relay on a 1990 Chevrolet Corvette is located in the relay bank on the passenger side of the engine compartment, mounted to the firewall near the brake booster. This is the most common location for C4 generation Corvettes from 1990 through 1994. If you are working on a 1990 Corvette, the fuel pump relay is part of a group of relays positioned on the right side of the engine bay, attached to the inner fender well or the firewall itself. Finding it is straightforward once you know where to look.

How to Locate the Fuel Pump Relay on Your 1990 Corvette

The fuel pump relay sits in a relay bank that contains multiple relays. According to owner reports and service documentation, the 1990 Corvette relay bank is located below the right side of the instrument panel, but the physical location in the engine compartment is on the passenger side firewall, next to the brake booster. The fuel pump relay is typically the first relay on the left when you are facing forward from the driver's seat. There are five relays in this bank: two from one wire harness and three from another.

Here is how to find it step by step:

  1. Open the hood and locate the brake booster on the driver's side. The fuel pump relay is mounted on the firewall next to the brake booster, on the passenger side of the engine bay.
  2. Look for a small black plastic relay that fits into a socket. The relay is about 1.5 inches square with a rectangular shape.
  3. Identify the relay bank. The fuel pump relay is part of a group of relays attached to the inner wheel well or the firewall. The fan relay is also nearby on the inner wheel well.
  4. Check the relay for markings. The fuel pump relay will have a wire harness that connects to the ECM and the fuel pump circuit.

Some owners have reported that the relay can also be found in the under-hood fuse box on the passenger side of the engine compartment. However, the firewall location is the most common and reliable spot for 1990 models.

What Does the Fuel Pump Relay Do?

The fuel pump relay controls the power supply to the fuel pump. When you turn the ignition key to the "on" position, the relay closes and sends power to the pump. This allows the pump to prime the fuel system before starting the engine. Once the engine is running, the relay stays closed to keep the pump operating. The relay also has a shut-off function: if the engine stalls or if the impact sensor is triggered, the relay opens and cuts power to the pump, preventing fuel from being pumped in an accident.

Symptoms of a Bad Fuel Pump Relay

If your fuel pump relay is failing, you may notice these common symptoms:

  • Engine cranks but does not start. The fuel pump will not prime if the relay is dead.
  • No fuel pump noise when you turn the key. You should hear a brief whirring sound from the rear of the car for about two seconds when the key is turned.
  • Intermittent starting problems. The car may start sometimes and fail other times.
  • Engine stalls while driving. The relay may fail intermittently, cutting power to the pump.

However, a bad relay is rarely the cause of running problems once the engine is started. If the pump primes when you turn the key on but the engine runs poorly, the issue is likely elsewhere.

How to Test the Fuel Pump Relay

Testing the relay is simple and requires only a multimeter or a test light.

  1. Locate the relay and remove it from its socket.
  2. Use a multimeter to check for continuity between the relay terminals. You should have continuity between terminals 30 and 87 when the relay is activated (when power is applied to the coil terminals).
  3. You can also swap the fuel pump relay with a known good relay, such as the horn relay, to see if the problem moves. This is a quick troubleshooting method that many owners use.

Where to Find the Fuses for the Fuel Pump

The 1990 Corvette has two fuel pump fuses. The primary fuel pump fuse is located in the interior fuse panel on the right side of the instrument panel. It is a 10-amp fuse labeled as number 14 in the fuse box. The secondary fuel pump fuse is located in the fuse holder under the hood and is also a 10-amp fuse, labeled as number 1 in the under-hood fuse holder.

If the fuel pump fuse is blown, check for a short circuit in the wiring, a failing fuel pump that draws too much current, or a clogged fuel filter that forces the pump to work harder. Always replace a blown fuse with one of the correct amperage rating.

Common Misconceptions About the Fuel Pump Relay Location

Some sources say the fuel pump relay is under the dash on the passenger side, behind the fuse panel. This is not accurate for the 1990 model. The 1990 Corvette relay is in the engine compartment, not inside the cabin. The confusion may come from later model years or from the fuel pump shut-off switch, which is located behind an access panel in the luggage compartment for some vehicles.

Another common mistake is confusing the fuel pump relay with the MAF power relay or the burn-off relay, which are located behind the battery. Those relays control the mass airflow sensor, not the fuel pump.

Why You Should Keep a Spare Fuel Pump Relay

Relays are inexpensive and easy to replace. A failed relay can leave you stranded. Many C4 Corvette owners carry a spare fuel pump relay in the glove box. The part number for the 1990 Corvette fuel pump relay is GM 13502674 or 14100455, which is also used from 1990 through 1994 models. The relay is a standard 4-pin or 5-pin relay that can be found at most auto parts stores.

How to Replace the Fuel Pump Relay

Replacing the fuel pump relay is a simple task that you can do in minutes.

  • Disconnect the negative battery cable before working on any electrical components.
  • Pull the old relay straight out of its socket. It may require a gentle tug.
  • Insert the new relay into the same socket. Make sure it is fully seated.
  • Reconnect the battery and test the fuel pump by turning the key to the "on" position. You should hear the pump prime.

The relay is located in the engine bay fuse box or on the firewall. If you are unsure, refer to the fuse box diagram or your owner's manual.

What to Do If the Fuel Pump Still Does Not Work

If you replace the relay and the fuel pump still does not run, check the following:

  • Fuses: Check both the primary and secondary fuel pump fuses.
  • Wiring: Inspect the wiring harness for damage, chafing, or loose connections. Test for power at the fuel pump connector at the rear of the car. To access this, remove the fuel fill door, the rubber boot, and disconnect the connector. Use a voltmeter to test for battery voltage with the key on. If you get no voltage, the problem is in the circuit, not the pump.
  • Fuel pump itself: If there is power but no pump noise, the pump may be faulty. Fuel pumps on C4 Corvettes are known to fail, especially on older models with high mileage.

Upgrading Your Fuel System: Why You Should Consider a KEMSO Fuel Pump

When it comes time to replace your fuel pump, choosing a high-quality replacement is essential for reliable performance and long life. KEMSO fuel pumps are an excellent choice for your 1990 Corvette.

KEMSO fuel pumps deliver high-performance, OEM replacement quality that you can count on for the long haul. Every KEMSO fuel pump is built to meet or exceed factory specifications, ensuring a perfect fit and reliable operation in your vehicle. Whether you drive a car, truck, SUV, motorcycle, or powersports vehicle, KEMSO has the right fuel pump for your application.

What sets KEMSO apart:

  • High Performance: KEMSO fuel pumps are engineered to deliver consistent fuel flow and pressure, even under demanding conditions. Your engine gets the fuel it needs to perform at its best.
  • OEM Replacement Quality: Every pump is designed as a direct replacement for your vehicle's original equipment. No modifications, no guesswork, just a straightforward installation.
  • Lifetime Warranty: KEMSO stands behind every product with a lifetime warranty. If you ever have an issue, KEMSO has your back. That is the confidence that comes from building quality products.

Visit KEMSO today: Find the perfect fuel pump for your vehicle at https://www.kemsoracing.com/. From everyday drivers to high-performance machines, KEMSO has the fuel pump you need to keep your engine running strong.

Final Thoughts

Finding the fuel pump relay on your 1990 Corvette is simple once you know it is located on the passenger side firewall next to the brake booster. The relay is part of a relay bank with five relays, and the fuel pump relay is the first one on the left. Always check the fuses and wiring before replacing the relay, and keep a spare relay in your car for emergencies. When it is time to replace the fuel pump, choose a KEMSO fuel pump for reliable performance and a lifetime warranty.

For professional-grade fuel pumps that deliver performance you can trust, check out KEMSO Racing at https://www.kemsoracing.com/. Their OEM replacement fuel pumps come with a lifetime warranty, giving you peace of mind with every mile you drive.


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