1982 Corvette Fuel Pump Relay Location: The Definitive Guide (C3 Chassis)

For owners of the 1982 Chevrolet Corvette (C3 generation), the fuel pump relay is located inside the primary fuse block under the hood, specifically in socket position number 10. Knowing this precise location is critical for diagnosing and resolving sudden no-start conditions, unexpected fuel pump failure, or intermittent running problems common to this classic model year. Unlike some myths or confusion surrounding earlier fuel systems, the '82 relay has a designated spot within the engine compartment's main electrical center.

Understanding the Context: Why the 1982 Relay Matters

The 1982 Corvette represents a unique transition point. While earlier C3 models often used carburetors, 1982 was the first year for the Cross-Fire Injection (CFI) system on base models. This fuel injection setup heavily relies on consistent electrical power delivered to the fuel pump. The relay acts as the essential switch, controlled by the engine computer (ECM), that powers the pump. A failing relay directly translates to a pump that doesn't run, starving the engine of fuel. Knowing its exact location allows for quick inspection and testing, bypassing unnecessary component replacements. Ignoring the relay as a potential culprit often leads owners down costly paths replacing pumps or sensors when a $20-$40 relay might be the real issue.

Locating the Engine Compartment Fuse Block

The heart of the Corvette's under-hood electrical system is the main fuse block. This black plastic housing, containing both fuses and relays, is easily accessible:

1. Open the Hood: Securely prop the hood.
2. Battery Area: The fuse block is positioned near the battery, specifically on the driver's side (left side when standing at the front of the car).
3. Near the Brake Master Cylinder: It's typically mounted on or very close to the inner fender wall, just ahead of the brake master cylinder reservoir. The location is generally straightforward to spot, being a prominent, rectangular black box with numerous wiring harnesses plugged into it.
4. Visibility: You should be able to see it clearly without removing other components. It sits relatively high in the engine bay for accessibility.

Identifying Socket Position #10

The fuse block cover is crucial for identification. It features a diagram mapping out the position and function of every fuse and relay.

1. Remove the Cover: Gently unclip the plastic cover from the fuse block itself. This usually involves squeezing small tabs on the sides or ends and lifting the cover straight up.
2. Locate the Diagram: The underside of this cover, and often the top surface of the fuse block near its edge, has a clearly printed legend or diagram. This legend lists positions sequentially (e.g., 1, 2, 3, ...) and identifies each slot's function.
3. Find Position 10: Scan the diagram specifically for position #10. The legend will explicitly state "FUEL PUMP RELAY" or potentially "FP RELAY" for this position.
4. Matching Physical Location: Look inside the now-exposed fuse block. The sockets are arranged in rows and columns. Each socket position is physically numbered inside the block itself, embossed into the plastic near each slot. Carefully locate the socket labeled "10".
5. Double-Check: Verify that the description on the legend for slot #10 explicitly states it is for the fuel pump relay. This is its designated home.

The Role of the Fuel Pump Relay (1982 Cross-Fire Injection)

Understanding why this relay exists and how it works clarifies why its location is so vital for diagnosis:

1. Heavy Current Handling: The fuel pump draws significant electrical current during operation. The relay is an electromagnetic switch that allows a small current from the ECM (via the "control" circuit) to command the relay to close its internal contacts. This closing action completes a separate, much higher-current circuit directly from the battery (via a fuse) to the fuel pump.
2. ECM Control: The ECM activates the relay only under specific conditions: when the ignition key is turned to "Run" (providing power) and crucially, when it receives a signal from the distributor (indicating the engine is cranking or running). This is a vital safety feature. If the engine stalls (like in an accident), the distributor stops sending the signal, the ECM cuts power to the relay, and the fuel pump shuts off, reducing fire risk.
3. Oil Pressure Safety Switch (NOT the Relay): It's critical to dispel a common misconception. The 1982 Corvette also has an oil pressure safety switch, usually mounted near the oil filter. This switch is NOT the primary fuel pump relay. It acts as a backup. If the main relay (position #10) fails while the engine is running, the oil pressure switch can take over and provide power directly to the pump once oil pressure builds above a certain threshold (typically around 4 PSI). However, the relay in the fuse block (#10) is absolutely necessary to initially power the pump during engine cranking/startup. You cannot rely solely on the oil pressure switch to start the car. Starting failures point directly to the relay or its control circuit.

Symptoms Pointing Directly to the Relay in Position #10

When the fuel pump relay fails or its circuit is compromised, specific and noticeable symptoms occur, centering around the fuel pump's inability to receive power:

1. Engine Cranks But Won't Start: This is the most classic sign. The starter turns the engine over, but no fuel is delivered because the pump isn't running due to a lack of signal at position #10.
2. No Fuel Pump Prime Sound: When you turn the ignition key to the "Run" position (before cranking), you should clearly hear the fuel pump whir for about 2 seconds as it primes the system. A complete lack of this prime sound strongly suggests an issue with the relay or its power supply. (Listen near the rear of the car, where the pump is located).
3. Engine Stalls Shortly After Starting: If the relay is intermittent or fails immediately after initial activation, the engine might start but then die within seconds as power to the pump cuts out.
4. Intermittent Starting/Stalling: A relay on the brink of failure can cause random no-start episodes or unexpected stalls that later resolve seemingly on their own.
5. Electrical Smell: While rare, a severely overheated or internally shorted relay might produce a noticeable electrical burning odor emanating from the fuse block area. Address this immediately.

Accessing and Testing the Relay in Socket #10

Testing requires simple tools: a multimeter (set to DC voltage) and maybe a small test light. Safety first: Always disconnect the NEGATIVE battery terminal before touching electrical components.

1. Locate Relay #10: Follow the steps above to identify and access socket position #10.
2. Understand Terminal Functions: Knowing what terminals do what within socket #10 is key for testing:
   • Power In (Terminal 30 / Feed): Receives constant battery power (when battery is connected) from a fuse (usually a high-amperage fuse like a 20A, check your diagram). This is the large power source to be switched.
   • Power Out to Pump (Terminal 87 / Output): Delivers switched power to the fuel pump and the oil pressure switch when the relay is activated. This is the "switched" high-current path.
   • Control Ground (Terminal 85): Provides the ground path needed to energize the relay's internal electromagnet when the ECM triggers it.
   • Control Signal from ECM (Terminal 86): Receives a switched +12V signal from the Engine Control Module (ECM) when ignition is in Run/Start and the distributor is pulsing. This +12V signal, combined with the ground on Terminal 85, activates the relay.
3. Test for Constant Power at Terminal 30:
   • Reconnect the battery negative terminal temporarily for testing.
   • Set multimeter to DC Volts (20V scale).
   • Identify terminal 30 in the socket (refer to your fuse block diagram or standard relay terminal numbering). You might need to back-probe the socket connector carefully with multimeter probes, or probe the corresponding wire entering the back of the block if accessible.
   • With Ignition OFF, you should read Battery Voltage (approx. 12.6V) between Terminal 30 and vehicle ground (engine block/chassis).
4. Test for ECM Control Signal at Terminal 86:
   • Turn Ignition Key to "RUN" (do not crank engine).
   • Probe Terminal 86 (control signal from ECM) and ground.
   • You should see Battery Voltage for roughly 2 seconds (while you hear the pump prime). The voltage may drop to zero or intermittently pulse if the distributor isn't rotating. This verifies the ECM is attempting to activate the relay.
5. Test for Ground at Terminal 85: (Ignition OFF)
   • Set multimeter to OHMS (Resistance) or use continuity/diode test mode.
   • Disconnect negative battery terminal again.
   • Measure resistance between Terminal 85 and a known good ground point (engine/chassis).
   • You should get very low resistance (near 0 Ohms) or hear a continuity beep. A high or infinite resistance indicates a bad ground connection for the relay control circuit.
6. Test Relay Operation (Output at Terminal 87):
   • Option 1 (Swapped Relay): If you suspect the relay is bad, the simplest test is often to swap it with an identical relay from another non-critical position (e.g., Horn relay - confirm function & amp rating first!). If the fuel pump then primes on "Run," the original position #10 relay is faulty.
   • Option 2 (Voltage Test):
     • Reconnect battery.
     • Set multimeter to DC Volts.
     • Probe Terminal 87 (output to pump) and ground.
     • Turn Ignition to "RUN."
     • You should see Battery Voltage appear for about 2 seconds at Terminal 87 (matching the prime period). If power reaches Terminal 30 and the control signals (86/85) are present, but no power appears at Terminal 87 during prime, the relay is defective.
7. Test Relay Socket Power Delivery: If the relay itself tests good, but no power reaches Terminal 87 and the pump isn't getting power (confirmed with test light/meter at pump power wire connection), the issue lies in the wiring between Terminal 87 and the pump/switch, or potentially the connector at socket #10 is damaged/corroded.

Replacing a Faulty Relay in Position #10

Replacement is straightforward once you've confirmed the relay is bad:

1. Disconnect Battery: Always disconnect the NEGATIVE (-) battery cable first.
2. Identify Relay Type: Carefully pull the suspect relay straight out of socket #10. Note its orientation and any markings. Standard Bosch-style automotive mini relays were common (see pictures below). The standard type is usually a 4-pin or 5-pin mini ISO relay. Record or photograph its terminal configuration and any part numbers (e.g., AC Delco D1747A is a common equivalent).
3. Purchase Exact Replacement: Source a new relay matching the exact terminal configuration (pin count and layout) and amperage rating (e.g., 20A, 30A). Cross-reference the GM part number or use standard automotive relays like:
   • Standard Motor Products RY-449
   • BWD (Advance Auto) R3180
   • AC Delco D1747A (often labeled GM 14063467 or similar)
   • Bosch 0 332 019 150 (or equivalent ISO Mini Relay)
4. Clean Socket: Inspect the socket contacts in position #10 for any corrosion, dirt, or bent pins. Clean with electrical contact cleaner if necessary and ensure pins are straight.
5. Insert New Relay: Align the new relay correctly according to the terminal layout in the socket and the markings on the relay base. Push firmly straight down until it seats completely. It should fit snugly.
6. Reconnect Battery: Reconnect the negative battery terminal.
7. Test Operation: Turn ignition to "RUN" and listen for the 2-second fuel pump prime. If heard, crank the engine – it should start normally.

Addressing Common Relay Position #10 Issues Beyond the Relay Itself

If replacing the relay doesn't solve the problem, the issue lies elsewhere in the circuit affecting socket #10:

1. Blown Fuse Powering the Relay: Find the fuse supplying constant power to Terminal 30 of the relay. This is typically a high-amperage fuse (e.g., 20A) located in the main under-hood fuse block. Check your fuse diagram. Use a multimeter to test the fuse or visually inspect it. Replace if blown.
2. Bad Ground Connection for Terminal 85: The ground path for the relay's electromagnet is critical. A corroded, loose, or broken ground wire (usually black or black/white, connected to ground near the ECM/engine block) will prevent activation. Trace the wire from the socket and clean/tighten its ground point.
3. Faulty ECM Control Signal (Terminal 86): If you don't see voltage at Terminal 86 during priming (Step 4 above), the ECM might be failing to send the signal. Causes include:
   • Faulty Distributor Pickup Coil (no signal to ECM).
   • Bad ECM Power Relay.
   • Wiring fault between ECM and Terminal 86.
   • Failed ECM (rare, but possible).
4. Damaged Wiring Harness/Connectors: Inspect the wiring harness plugging into the fuse block. Look for corrosion, melted plastic, chafed wires, or loose terminals specifically affecting socket #10's circuits (power in, power out, control signals). Repair or replace as needed.
5. Corrosion in Fuse Block Socket: Severe corrosion within the socket for position #10 itself can prevent electrical contact even with a good relay. Cleaning may help; significant damage might require fuse block replacement or terminal replacement.
6. Faulty Ignition Switch: While unlikely to only affect the fuel pump relay signal, a failing ignition switch interrupting power during "Run" could mimic a relay failure. If the prime sound is inconsistent or non-existent across multiple circuits, suspect the switch.

Conclusion: Confidence Starts at Relay Position #10

Troubleshooting a non-starting or stalling 1982 Corvette often hinges on understanding its electrical heart. The fuel pump relay, decisively located in socket position #10 of the primary under-hood fuse block, is a critical gatekeeper. Its failure prevents the fuel pump from receiving power, instantly halting the engine. By learning its exact location, function, testing procedures, and replacement process, you arm yourself with the most practical diagnostic step for one of the most common failure points on these iconic C3 models. Checking or swapping this relay is nearly always the first and easiest intervention when faced with no fuel pump prime or an engine that cranks but refuses to start. Knowing you have accurate information on this specific '82 relay location saves time, money, and frustration, getting you back behind the wheel of your classic Corvette faster. Remember position #10 – it's your key to reliable fuel pump operation.

Appendices (Visual Aids & Reference)

• Appendix A: Fuse Block Legend & Position #10 Identification: (Link or describe detailed photos showing fuse block cover legend clearly marking "FUEL PUMP RELAY" at position #10, and the physical socket #10 inside the exposed block).
• Appendix B: Relay Terminal Identification Diagram: (Show diagram clearly labeling Terminals 30, 87, 85, 86 on a standard Bosch-type relay).
• Appendix C: 1982 Fuel Pump Relay Wiring Diagram Snippet: (Highlight the specific path: Battery -> Fuse -> Terminal 30 Relay #10; Terminal 87 Relay #10 -> Fuel Pump/Oil Pressure Switch; ECM -> Terminal 86 Relay #10; Terminal 85 Relay #10 -> Ground).
• Appendix D: Troubleshooting Flowchart:
  1. Symptom: No Fuel Pump Prime Sound / Cranks, No Start.
  2. Step 1: Listen for fuel pump prime (2 secs with key in "RUN").
  3. No Prime Sound? Proceed to Step 2.
  4. Prime Sound Heard? Problem likely elsewhere (fuel pressure, injectors, ignition).
  5. Step 2: Locate & inspect Fuse Block Relay in Position #10. Check for visual damage/overheating. Try swapping with known good relay (e.g., Horn).
  6. Prime Sound Returns? Bad Relay. Replace it in position #10.
  7. Still No Prime? Proceed to Step 3.
  8. Step 3: Verify constant Battery Voltage at Terminal 30 of Socket #10 (Relay Removed) with Ignition OFF.
  9. No Voltage? Check/maintain power fuse supplying terminal 30 (likely 20A). Check wiring back to battery. Inspect fuse block power feed.
  10. Voltage Present? Proceed to Step 4.
  11. Step 4: Verify +12V signal at Terminal 86 of Socket #10 (Relay Removed) with Ignition in "RUN" for 2 secs (meter/test light).
  12. No Signal? Problem in ECM control circuit: Check ECM power relay, ECM power grounds, Distributor pickup coil, wiring ECM -> Terminal 86, potential ECM failure.
  13. Signal Present? Proceed to Step 5.
  14. Step 5: Verify good ground at Terminal 85 of Socket #10 (Relay Removed) - measure resistance to chassis ground (should be near 0 Ohms).
  15. High Resistance? Find and clean/repair ground connection for Terminal 85 (wire usually ends at engine block/chassis near ECM).
  16. Good Ground? Proceed to Step 6.
  17. Step 6: Verify output voltage at Terminal 87 of Socket #10 when relay is commanded ON (use known good relay if needed). Should see ~12V for 2 secs in "RUN".
  18. Voltage Present? Problem downstream of Terminal 87 (Fuel pump fuse, wiring to pump/switch, oil pressure switch itself, pump itself).
  19. No Voltage? Relay is bad OR socket contacts for Terminal 30/87 are corroded/damaged despite good relay. Inspect socket carefully. Clean terminals or replace fuse block/socket parts as needed.