Here's a breakdown of how to test it, remembering that specific locations might vary slightly depending on your exact model:
1. Locate the Fuel Pump Relay:
* Consult your owner's manual: This is the best place to find the exact location of the fuel pump relay. The manual will often have a diagram of the fuse box and relay panel.
* Common locations: The relay is typically located in the under-hood fuse box or, less commonly, in the interior fuse panel (near the steering column). It's often labeled, but not always clearly. Sometimes it's just a generic "Fuel Pump" relay, other times it might be part of a larger system (like a fuel injection relay).
2. Identify the Fuel Pump Relay:
* Visual inspection: Look for relays that are similar in size and shape. Often, a diagram on the fuse box cover will help identify the relay. The diagram might show a fuel pump symbol.
* Use a multimeter (optional): If you're unsure, you can use a multimeter to test continuity between the relay's terminals. However, this requires a bit more electrical knowledge. We'll discuss this below if needed.
3. Testing Methods (Choose ONE method):
Method A: Simple Swap (Easiest):
* Find a similar relay: Locate another relay of the same type in your fuse box (often the horn relay, wiper relay, etc., are similar).
* Swap the relays: Carefully remove the suspected fuel pump relay and swap it with a known good relay.
* Test the fuel pump: Try to start the car. If it now starts, the original relay was faulty. If not, there's another issue. Important: Always replace the relay with the correct type after testing.
Method B: Using a Multimeter (More Advanced):
This requires a basic understanding of using a multimeter to check continuity and voltage.
* You'll need: A multimeter set to the appropriate range (continuity or ohms, and voltage).
* With the relay removed:
* Continuity: Check the continuity between the relay's coil terminals. There should be continuity (a low resistance reading) when the relay is NOT energized.
* Voltage: With the key in the "ON" position (engine off), check for voltage across the power terminals of the relay. You should have battery voltage (around 12V).
* Ground: Ensure the ground terminals of the relay have a good ground connection to the car's chassis.
Interpretation of Multimeter Results (Method B):
* No continuity across coil terminals: The relay coil is likely open, and the relay is faulty.
* No voltage at power terminals (with key ON): The problem might be with the wiring leading to the relay, or a faulty fuse in the circuit.
* No ground: A poor ground connection prevents the relay from functioning correctly.
4. If the Relay is Faulty:
Replace the relay with a new one of the *exact same type* from a reputable auto parts store. Don't just grab any relay; the amperage and voltage ratings must match.
Important Considerations:
* Fuse check: Always check the associated fuse(s) for the fuel pump circuit before testing the relay. A blown fuse can prevent the relay from working correctly.
* Other possible causes: A faulty fuel pump, wiring issues, or even a problem with the fuel pump control module (PCM or ECM) can also prevent the fuel pump from working. If the relay is good, these are areas to investigate further.
* Professional help: If you're not comfortable working with car electronics, it's always best to seek help from a qualified mechanic.
Remember to reconnect the negative battery cable after completing your tests. Good luck!
