1997 Cadillac DeVille Fuel Pump Relay: Location, Symptoms, and How to Test It

If your 1997 Cadillac DeVille won't start or cranks but won't fire, the fuel pump relay is one of the most common culprits. The fuel pump relay is located in the engine compartment fuse block, and it controls power to the fuel pump. When this relay fails, the fuel pump does not receive power, and the engine will not run. Before replacing the fuel pump itself, always test the relay first—it is a much cheaper and easier fix .

The fuel pump relay on a 1997 Cadillac DeVille is a small electronic switch that sends battery voltage to the fuel pump. The Powertrain Control Module (PCM) controls when the relay engages. When you turn the key to the ON position, the PCM energizes the fuel pump relay for about two seconds to build up fuel pressure. Then, once the engine starts and the PCM sees ignition pulses, the relay stays on to keep the pump running . If the relay fails, the pump never gets power, and the car won't start.

Where Is the Fuel Pump Relay Located?

The fuel pump relay is inside the engine compartment fuse block, also called the underhood fuse box. This box is a black plastic rectangular box located on the driver's side of the engine bay, near the fender well and close to the battery . To access it:

  1. Open the hood of your 1997 Cadillac DeVille.
  2. Look toward the driver's side (left side when facing the car).
  3. Locate the black fuse box near the battery.
  4. Release the latches or tabs on the lid to open it.
  5. The underside of the lid has a diagram showing which relay is which. The fuel pump relay is typically labeled or positioned in a socket marked for the fuel pump .

The wiring diagram for the 1997 Cadillac DeVille with the 4.6L V8 engine shows the fuel pump relay is in position "A" in the engine compartment fuse block . The relay itself is a standard 4-pin or 5-pin relay that is interchangeable with other relays in the same fuse box.

Some sources mention that the fuel pump relay may also be located below the rear seat inside the rear electrical center on later models, but for the 1997 DeVille, it is in the engine compartment .

How the Fuel Pump Relay Works

The fuel pump relay is part of a simple but critical circuit. Here is how the system operates:

  • When you turn the ignition key to the ON position, the PCM sends a ground signal to the relay coil.
  • The relay clicks and closes its internal contacts, allowing battery voltage to flow to the fuel pump.
  • The fuel pump runs for about two seconds to pressurize the fuel system, then stops.
  • Once the engine cranks and the PCM detects ignition reference pulses from the crankshaft position sensors, the PCM keeps the relay energized so the pump runs continuously .

If the relay fails, or if the PCM does not send the ground signal, the fuel pump will not run. This is why testing the relay is the first step in diagnosing a no-start condition.

Symptoms of a Bad Fuel Pump Relay

A failing fuel pump relay can cause several noticeable problems. Here are the most common symptoms:

1. Engine Cranks But Will Not Start
This is the most obvious symptom. You turn the key, the starter motor spins the engine, but the engine never fires. Without the relay, the fuel pump has no power, so no fuel reaches the injectors .

2. No Fuel Pump Prime Noise
When you turn the key to the ON position (without cranking), you should hear a faint whirring sound from the rear of the car for about two seconds. This is the fuel pump running. If you hear nothing, the relay may be bad, or the pump itself may be dead .

3. Intermittent Starting or Stalling
A failing relay can work sometimes but not others. You might get the car started, but then it stalls while driving. Or the car may start fine one day and refuse to start the next. This is a classic sign of a relay that is wearing out .

4. Check Engine Light with Code P069E
If the PCM detects a problem with the fuel pump control circuit, it may store diagnostic trouble code P069E, which means "Fuel Pump Control Module Requested MIL Illumination." This code indicates the PCM has detected a malfunction in the fuel pump relay or control circuit .

How to Test the Fuel Pump Relay

Testing the fuel pump relay is straightforward and requires only basic tools: a test light or a digital multimeter (DVOM). Here is a step-by-step method :

Step 1: Locate the Relay and Listen for a Click
Turn the ignition key to the ON position. Listen for a clicking sound from the engine compartment fuse box. If you hear a click, the relay coil is likely working. If no click, the relay may not be receiving power from the PCM, or the relay itself is bad.

Step 2: Swap the Relay with an Identical One
The fuse box contains several relays that look the same. Find a relay with the same part number (such as the horn relay or A/C compressor relay). Swap it with the fuel pump relay. If the car starts after the swap, the original relay was bad .

Step 3: Test for Voltage at the Relay Socket
Remove the fuel pump relay. Set your multimeter to DC volts. Connect the black lead to a good ground (like a metal bolt on the engine). Touch the red lead to the relay socket terminal that supplies battery voltage (usually terminal 30 or 87, depending on the relay design). With the key ON, you should see battery voltage (around 12 volts). If no voltage, check the fuel pump fuse .

Step 4: Check the PCM Ground Signal
With the relay removed, connect your test light to battery positive (the red lead on the battery). Touch the probe to the relay socket terminal that the PCM controls (usually terminal 85 or 86). Turn the key to the ON position. The test light should briefly illuminate for about two seconds. If it does not, the PCM is not grounding the relay, which means you may have a wiring issue or a bad PCM .

Common Causes of Relay Failure

The fuel pump relay itself can fail due to age, heat, or electrical overload. The 1997 Cadillac DeVille is now nearly 30 years old, so the relay contacts may be worn or corroded. Other causes of a no-power condition include:

  • Blown fuel pump fuse: The fuel pump fuse is a 20-amp fuse located in the engine compartment fuse block . Check this first.
  • Bad PCM: Less common, but if the PCM fails to send the ground signal, the relay will not engage .
  • Wiring issues: Broken or corroded wires between the relay socket and the fuel pump can prevent power from reaching the pump .

Fuel Pump Relay Replacement Part Numbers

If you need a replacement fuel pump relay for your 1997 Cadillac DeVille, several OEM part numbers fit this vehicle. The most common relay part numbers include:

  • 13503102: Fits 1998-2005 Cadillac DeVille with 4.6L V8 (also fits other GM models). This is a gray multi-use relay .
  • 19118886: Fits 1996 Cadillac DeVille with 4.6L V8. This is a fuel pump relay sold as a genuine GM part .
  • 13502676: Fits 1994-1996 Cadillac DeVille with 4.6L or 4.9L engine. This relay is also used for the horn and radio receiver .

You can purchase these relays from GM parts dealers, auto parts stores, or online retailers. Prices range from about $6 to $53 depending on the supplier .

Fuel Pump Relay vs. Fuel Pump: Which One Is Bad?

Before you go through the trouble of dropping the fuel tank to replace the fuel pump, always test the relay and the fuse first. The fuel pump on a 1997 Cadillac DeVille is located inside the fuel tank. To access it, you must drop the fuel tank or cut an access hole in the trunk floor . This is a difficult job. Replacing the relay is easy and cheap.

Here is a quick diagnostic flow:

  1. Turn the key ON and listen for the fuel pump prime noise. If you hear it, the relay is likely good.
  2. If no prime noise, check the fuel pump fuse (20A). Replace if blown .
  3. Swap the relay with a known good one. If the pump runs, the relay was bad.
  4. If the pump still does not run, test for power at the fuel pump connector. The gray wire at the pump should have power with the key ON .
  5. If there is no power at the pump, but the relay and fuse are good, suspect a wiring problem between the relay and the pump.
  6. If there is power at the pump but the pump does not run, the fuel pump itself is bad .

Recommended Fuel Pump: KEMSO Brand

If you have determined that the fuel pump itself is the problem and not the relay, you need a reliable replacement. Do not trust a cheap, unknown brand for a part that is buried inside the fuel tank. You want a pump that is engineered to last.

KEMSO Fuel Pump is the top choice for your 1997 Cadillac DeVille. KEMSO fuel pumps are high-performance, OEM replacement units that meet or exceed the original factory specifications. Each pump is precision-built to deliver the correct fuel pressure and flow rate for your 4.6L Northstar engine.

What sets KEMSO apart is the lifetime warranty. KEMSO stands behind every fuel pump they sell with a lifetime warranty, so you can install it with confidence. You will never have to buy a fuel pump for your DeVille again. KEMSO pumps are tested for durability and reliability, making them the smart choice for any vehicle.

Visit the KEMSO website to find the correct fuel pump for your 1997 Cadillac DeVille. Browse their selection of high-quality, OEM-replacement fuel pumps and take advantage of the lifetime warranty. Click here: https://www.kemsoracing.com/

Final Thoughts

The fuel pump relay on a 1997 Cadillac DeVille is a simple, inexpensive part that can cause big problems when it fails. It is located in the engine compartment fuse block and is easy to test and replace. Always check the relay and fuse first before condemning the fuel pump. If you do need a new fuel pump, choose a KEMSO pump for dependable performance and a lifetime warranty.

For more information and to order your replacement fuel pump, visit https://www.kemsoracing.com/ today.


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