You press the washer stalk and nothing happens. No fluid, no spray, nothing. Before you spend money on a new pump or a mechanic, the problem is often a blown fuse or a bad relay two cheap parts you can check yourself in minutes. Knowing how to check the windshield washer pump fuse and relay saves you time, money, and the frustration of driving with a dirty windshield you can't clean.

What does the windshield washer pump fuse and relay do?

Your washer pump is a small electric motor. Like any motor, it needs electrical protection. The fuse acts as a safety device if too much current flows through the circuit, the fuse blows and cuts power to protect the wiring and pump from damage. The relay is a small switching device that lets a low-power signal from your wiper stalk activate the higher-power circuit that runs the pump motor.

When either one fails, the pump gets no power. You'll hear no humming sound when you activate the washer, and no fluid comes out of the nozzles. The wipers themselves might still work fine since they run on a separate circuit.

How do I know if my washer pump fuse is blown?

The fastest way to tell is a visual check. Pull the suspected fuse from the fuse box and hold it up to a light. A good fuse has an intact metal strip or wire connecting the two prongs. A blown fuse has a broken strip it might look burned, melted, or visibly split in the middle.

Some vehicles use opaque fuses where you can't see through them easily. In that case, you can use a multimeter set to continuity mode. Touch one probe to each prong of the fuse. If the meter beeps, the fuse is good. If there's no beep, it's blown.

Another clue: if the fuse blows repeatedly after you replace it, you likely have a short circuit somewhere in the washer pump wiring or the pump itself is drawing too much current. You can check the correct fuse amp rating for your washer pump to make sure you're not installing the wrong size.

Where is the windshield washer pump fuse located?

Most vehicles have two fuse boxes one under the hood (engine compartment) and one inside the cabin, often under the dashboard on the driver's side. The washer pump fuse is usually in the under-hood fuse box because the pump is at the front of the vehicle near the washer fluid reservoir.

Your owner's manual has a fuse box diagram that labels every fuse. Look for a label like "WASH," "WASHER," "WSHW," or "WIPER/WASHER." The fuse number and amperage are listed there. If you've lost the manual, the fuse box lid itself often has a printed diagram.

If you drive a Ford F-150, the fuse location can vary by model year, so it helps to look at a year-specific guide for the F-150 washer pump fuse.

How do I check the windshield washer pump relay?

The relay is a little cube-shaped component, usually black or gray, that plugs into the fuse box. Here's how to test it:

  1. Find the relay. Check your owner's manual or the fuse box cover diagram for the relay labeled "WASHER" or "WIPER." Relays are larger than fuses and typically square.
  2. Swap test. Many relays in your fuse box are identical. Pull out the washer relay and swap it with another relay of the same part number (like the horn relay). If the washer starts working and the horn stops, you've confirmed the relay was bad.
  3. Listen for a click. Have someone press the washer stalk while you place your finger on the relay. You should feel or hear a small click. No click usually means the relay isn't activating it could be bad or it might not be getting a signal from the switch.
  4. Test with a multimeter. Remove the relay and check continuity across the switching pins (refer to the relay's pin diagram, often printed on the side). Apply 12V to the coil pins with a battery or power probe. If the switch pins don't show continuity when energized, the relay is faulty.

If the relay clicks but the pump still doesn't work, the problem may be elsewhere. This situation is covered in more detail in our guide on washer pump not spraying while the wipers work, which walks through diagnosing other common causes.

What tools do I need?

  • Vehicle owner's manual (or a photo of the fuse box diagram)
  • Fuse puller (usually stored in the fuse box)
  • Spare fuses in the correct amperage
  • A multimeter (optional but helpful)
  • A 12V test light (optional)

You don't need expensive equipment. A basic multimeter from any hardware store works fine, and many people do this whole check with just their eyes and a spare fuse.

Common mistakes when checking washer pump fuses and relays

Using the wrong fuse rating. If you replace a 10A fuse with a 20A fuse, you remove the protection the fuse provides. This can overheat the wiring and cause a fire. Always match the amperage printed on the old fuse or listed in your manual.

Skipping the relay check. Many people replace the fuse and assume the job is done. But if the relay is stuck open, even a brand-new fuse won't fix the problem. Test the relay too.

Ignoring corroded terminals. Sometimes the fuse and relay are both fine, but the terminals they plug into are corroded or loose. Pull them out and look at the metal contacts. Clean them with electrical contact spray if you see green or white buildup.

Not checking ground connections. The pump needs a good ground to work. A corroded or loose ground wire near the washer reservoir can mimic a blown fuse symptom. You can find the ground point by tracing the pump's wiring harness.

Quick diagnostic checklist

Before you start, turn the ignition to the "on" position (engine doesn't need to run). Then work through this list:

  1. Activate the washer function and listen near the front of the car. No sound from the pump? Continue.
  2. Locate the washer fuse using your fuse box diagram.
  3. Pull the fuse and inspect it visually for a broken strip.
  4. If it's blown, replace it with the same amperage rating.
  5. Test the washer again. If the new fuse blows immediately, you have a short in the wiring or pump.
  6. If the fuse is fine, locate the washer relay.
  7. Try the swap test with a matching relay from the fuse box.
  8. If swapping fixes it, buy a replacement relay. If not, the issue is likely the pump motor, wiring, or the washer switch on the stalk.

Most of the time, you'll find your answer within the first four steps. Checking the fuse and relay takes less than 10 minutes and costs nothing if the parts are still good or a few dollars at most if you need a replacement. For reference on fuse types and ratings used across most passenger vehicles, Littlefuse publishes useful technical specifications.

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