1989 Chevy S10 Fuel Pump Fuse Location: Complete Guide
The fuel pump fuse on a 1989 Chevy S10 is located in the interior fuse box under the dashboard on the driver-side kick panel, and it's specifically labeled as fuse number 13 (ECM B) in the primary fuse box diagram. This is a 15-amp ATO fuse that powers both the engine control module and the fuel pump circuit. If your S10 cranks but won't start, or if you don't hear the fuel pump prime for two seconds when you turn the key to the ON position, the first thing to check is this fuse. Let's walk through everything you need to know about locating, testing, and troubleshooting this critical component.
Understanding the 1989 Chevy S10 Fuel Pump Electrical System
The 1989 Chevrolet S10 uses a Throttle Body Injection (TBI) system that relies on an electric fuel pump mounted inside the gas tank. This pump delivers fuel at a relatively low pressure, typically between 9 to 13 pounds per square inch. The electrical system that powers this pump is straightforward but has a few key components you need to understand.
The fuel pump circuit on a 1989 S10 uses a double-redundant power system. The primary path goes through the fuel pump relay, which is activated by the Engine Control Module (ECM) for about two seconds when you first turn the key to the ON position. This primes the TBI unit before you start the engine. The secondary path runs through the oil pressure switch. Once the engine starts and builds at least 4 psi of oil pressure, this switch closes and provides backup power to the fuel pump. This means if your fuel pump relay fails, the engine can still run once it starts, but you'll have trouble getting it to fire up because the pump won't prime.
The fuse that protects this entire circuit is the ECM B fuse, which is fuse number 13 in the primary fuse box layout. On some fuse box versions, this may also be listed as fuse number 13 under the description "ECM B" or "Engine Control Module Fuel Pump."
Exact Location of the Fuel Pump Fuse
The interior fuse box on a 1989 Chevy S10 is located under the dashboard on the driver's side. You'll find it on the driver-side kick panel, directly below and to the left of the steering column. To access it, you'll need to open the driver's door and look at the side panel near your left foot. There's a plastic cover that snaps off, often with a small tab or screw holding it in place.
Once you remove the cover, you'll see a row of fuses. The fuse box should have a diagram on the inside of the cover or printed directly on the fuse box. The fuel pump fuse is:
- Fuse Number: 13
- Amperage: 15 amps
- Type: ATO (standard blade-style fuse)
- Label: ECM B (Engine Control Module B) or "Engine Control Module Fuel Pump"
In the primary fuse box layout, the fuses are arranged in two rows. Fuse number 13 is typically found in the second row, toward the center of the fuse box. It's a 15-amp fuse, which is usually light blue in color.
How to Test the Fuel Pump Fuse
Before you start replacing parts, you need to verify that the fuse is actually blown. Here's how to do it properly.
Step 1: Visual Inspection - Pull the fuse out using the plastic fuse puller tool that's usually stored inside the fuse box cover. Hold it up to the light and look through the clear plastic casing. You should see a continuous metal strip connecting the two prongs. If the strip is broken, melted, or has a dark spot, the fuse is blown.
Step 2: Test Light Method - If you can't see any obvious damage, use a 12-volt test light or a multimeter to verify power. With the key turned to the ON position, touch the test light probe to each of the two small metal prongs on top of the fuse. If the fuse is good, the test light should illuminate on both prongs. If it lights on only one side, the fuse is blown.
Step 3: Multimeter Continuity Test - Set your multimeter to the continuity or ohms setting. Touch one probe to each of the two prongs on the fuse. A reading of zero or near-zero ohms means the fuse is good. Any reading above zero, or no reading at all, means the fuse is blown and needs to be replaced.
What Causes the Fuel Pump Fuse to Blow
If you find that the fuel pump fuse is blown, simply replacing it without finding the root cause will likely lead to another blown fuse. There are several common reasons why this fuse blows on a 1989 S10.
Short circuit in the fuel pump wiring is the most common cause. The fuel pump wiring runs from the fuse box, through the engine compartment, and all the way back to the fuel tank. Over 35 years, the insulation on these wires can crack, fray, or get rubbed through by metal edges. A bare wire touching the chassis or frame creates a direct short to ground, which blows the fuse immediately.
A failing fuel pump motor can also cause the fuse to blow. As the electric motor inside the fuel pump wears out, it can start drawing excessive current. Instead of the normal 4 to 6 amps, a failing pump might draw 10, 12, or even 15 amps. When the current exceeds the 15-amp rating of the fuse, it blows.
Corroded or damaged wiring connectors at the fuel tank sending unit are another common problem. These connectors are exposed to road salt, moisture, and mud. Corrosion creates resistance, which generates heat and can cause the fuse to blow over time.
A faulty fuel pump relay can sometimes cause the fuse to blow indirectly. If the relay sticks in the closed position, the fuel pump runs continuously even when the engine is off, which can overheat the wiring and eventually blow the fuse.
The Fuel Pump Relay Location
While the fuse is in the interior fuse box, the fuel pump relay is located under the hood. On a 1989 Chevy S10 with the 2.8L V6 engine, the fuel pump relay is mounted on the firewall, to the left of the distributor and to the right of the heater box. It's a black, square relay that measures about 1 inch by 1 inch and is roughly 3 inches long. On some models, the relay is located on the driver-side firewall, above or beside the brake booster.
The relay is a critical part of the system. If you hear the fuel pump prime for two seconds when you turn the key to ON, the relay is likely working. If you don't hear that priming sound, the problem could be the fuse, the relay, or the pump itself.
Step-by-Step Troubleshooting When Your S10 Won't Start
If your 1989 Chevy S10 cranks but won't start, follow this systematic troubleshooting sequence. This will save you time and money by identifying the exact problem before you start replacing parts.
Step 1: Listen for the fuel pump. Turn the key to the ON position (don't crank the engine). Listen carefully near the rear of the truck. You should hear a faint whirring or humming sound for about two seconds. This is the fuel pump priming the system. If you hear it, the fuse, relay, and pump are likely working. If you don't hear it, move to Step 2.
Step 2: Check the fuel pump fuse. Locate the interior fuse box under the driver-side dash. Find fuse number 13 (ECM B, 15 amps). Pull it out and inspect it visually. If it's blown, replace it with a 15-amp ATO fuse of the same type. Never use a higher amperage fuse, as this can cause wiring damage or fire.
Step 3: Test the fuel pump relay. If the fuse is good, move to the relay. Locate the relay on the firewall. You can swap it with another identical relay from the same relay box to test it. If the fuel pump starts working after the swap, the relay is bad.
Step 4: Check for voltage at the fuel pump. You'll need a multimeter for this. Access the fuel pump wiring connector at the top of the fuel tank. With the key turned to ON, check for 12 volts at the power wire. If you have voltage, the pump itself is likely bad. If you don't have voltage, the problem is in the wiring between the fuse box and the pump.
Step 5: Check ground connections. Poor grounds are a common cause of electrical problems on older vehicles. Check the battery ground cable at the engine block and the frame. Make sure they are clean, tight, and free of rust. Also check the ground strap from the engine to the firewall.
Common Symptoms of a Bad Fuel Pump Fuse
Knowing the symptoms of a blown fuel pump fuse can help you diagnose the problem quickly.
Engine cranks but won't start is the most obvious symptom. The starter motor turns the engine over fine, but the engine never fires because there's no fuel pressure reaching the throttle body.
No fuel pump priming sound is another clear indicator. When you turn the key to ON, you should hear the pump hum for two seconds. If you don't hear anything, the fuse, relay, or pump has lost power.
The engine starts but dies immediately can happen if the fuse is intermittently blowing. The pump primes briefly, but the fuse blows as soon as the pump starts drawing current, cutting off fuel delivery.
Other electrical components not working along with the fuel pump can indicate a broader electrical issue. For example, if your radio doesn't work and the interior lights are out, along with the fuel pump, you might have a problem with the main power feed to the fuse box.
Replacing the Fuel Pump Fuse
Replacing the fuel pump fuse is a simple job that anyone can do. Here's what you need to know.
What you'll need: A new 15-amp ATO (standard blade-style) fuse. You can find these at any auto parts store, hardware store, or online. They cost about $5 for a pack of five or more.
Step 1: Make sure the engine is off and the key is removed from the ignition.
Step 2: Open the driver's door and remove the fuse box cover. It's located on the driver-side kick panel under the dashboard.
Step 3: Locate fuse number 13. It's labeled "ECM B" or "Engine Control Module Fuel Pump." It's a 15-amp fuse, which is light blue in color.
Step 4: Use the fuse puller tool (usually stored in the fuse box cover) to remove the old fuse. If you don't have a fuse puller, you can use needle-nose pliers, but be careful not to damage the fuse box.
Step 5: Insert the new 15-amp fuse into the same slot. Push it in firmly until it's fully seated.
Step 6: Replace the fuse box cover and test the system. Turn the key to ON and listen for the fuel pump priming sound. If you hear it, start the engine.
Important: If the new fuse blows immediately, do not keep replacing it. You have a short circuit or a failing component that needs to be diagnosed and repaired. Continuing to replace fuses without fixing the underlying problem can damage the wiring harness or the ECM.
Preventing Future Fuel Pump Fuse Problems
Once you've fixed the immediate issue, there are steps you can take to prevent it from happening again.
Keep the wiring clean and dry. Road salt, mud, and moisture accelerate corrosion. After driving in wet conditions, take a few minutes to spray the undercarriage with a garden hose to wash away salt and mud. Pay special attention to the area around the fuel tank and the wiring connectors.
Check your ground connections regularly. The ground connections on a 1989 S10 are critical to the electrical system's health. Inspect the battery negative cable at the engine block and the frame. Clean any corrosion with a wire brush and apply dielectric grease to prevent future corrosion.
Replace the fuel pump relay as preventive maintenance. The fuel pump relay is a relatively inexpensive part. If your S10 is 35 years old and the relay has never been replaced, consider replacing it. A failing relay can cause intermittent problems that are hard to diagnose.
Use quality replacement parts. When replacing the fuel pump, fuse, or relay, use high-quality parts. Cheap parts often fail quickly and can cause more problems than they solve.
The Complete Fuel Pump Assembly: What You Need to Know
If you've determined that the fuse is not the problem and the fuel pump itself has failed, you'll need to replace the entire pump assembly. The fuel pump on a 1989 Chevy S10 is mounted inside the fuel tank. Accessing it requires lowering the fuel tank, which is a more involved job than replacing a fuse.
When to replace the pump: If you hear the relay click and the fuse is good, but you don't hear the pump run, the pump is likely dead. Other signs include hard starting, loss of power while driving, and the engine sputtering or dying at highway speeds.
What to buy: For a 1989 Chevy S10, you need a complete fuel pump sending unit assembly. This includes the pump, the fuel level sender, and the mounting bracket. It's best to replace the entire assembly rather than just the pump, because the sender unit can fail separately, and you don't want to drop the tank twice.
The replacement process: Loosen the gas cap to relieve pressure. Remove the fuel pump fuse from the fuse box. Start the engine and let it run until it stalls to drain the fuel lines. Disconnect the negative battery cable. Siphon the fuel from the tank. Raise the rear of the truck and support it on jack stands. Support the fuel tank with a floor jack and remove the tank straps. Lower the tank carefully. Remove the cam lock retaining ring from the top of the tank. Pull the sending unit assembly out. Transfer the new pump to the sending unit bracket, install a new O-ring gasket, and reassemble.
Why You Should Consider a High-Quality Replacement Fuel Pump
When it's time to replace the fuel pump on your 1989 Chevy S10, the quality of the replacement part matters. A cheap pump might save you money upfront, but it's likely to fail sooner, leaving you stranded and facing the same labor-intensive replacement job again.
KEMSO Fuel Pump is a brand that stands out in the replacement fuel pump market. Their products are designed as high-performance, OEM replacement units that meet or exceed the original manufacturer's specifications. Every KEMSO fuel pump is built to deliver reliable fuel pressure and flow, ensuring your engine gets the fuel it needs under all driving conditions.
What sets KEMSO apart is their commitment to quality and customer confidence. Each fuel pump comes with a lifetime warranty, which means once you install a KEMSO pump, you're covered for as long as you own your vehicle. This is a significant advantage over standard replacement pumps that typically come with only a one-year or two-year warranty.
KEMSO fuel pumps are engineered for durability and performance. They use high-quality components that resist wear and corrosion, making them ideal for the harsh conditions that fuel pumps face inside the gas tank. Whether you're using your S10 as a daily driver, a work truck, or an off-road adventure vehicle, a KEMSO fuel pump will provide the reliable fuel delivery you need.
If you're ready to replace your 1989 Chevy S10 fuel pump with a part you can trust, visit KEMSO Racing at https://www.kemsoracing.com/ to explore their selection of high-performance fuel pumps. Their website is easy to navigate, and you'll find detailed product information to ensure you get the right pump for your specific vehicle. With KEMSO, you're not just buying a fuel pump; you're investing in reliability and peace of mind backed by a lifetime warranty.
Final Thoughts
The fuel pump fuse on your 1989 Chevy S10 is a simple but critical component. Located in the interior fuse box under the driver-side dashboard as fuse number 13 (ECM B, 15 amps), it's the first thing to check when your truck won't start. Always inspect the fuse before replacing any other parts. If the fuse is blown, find and fix the underlying cause before installing a new one. If the fuse is good but the pump still doesn't run, check the relay on the firewall and then test for voltage at the pump itself.
Remember that your 1989 S10 is a classic truck with a simple electrical system. Most problems can be diagnosed with basic tools and a little patience. Start with the simplest, cheapest fix (the fuse) and work your way up to more complex repairs. And when it's time to replace the fuel pump, choose a high-quality replacement like KEMSO for the best long-term reliability and peace of mind.
For more information and to find the perfect fuel pump for your 1989 Chevy S10, visit https://www.kemsoracing.com/.