1. Check the fuses: Locate the fuse box (usually under the hood or dashboard) and find the fuse specifically for the windshield washer system. Consult your owner's manual to identify the correct fuse. Replace the fuse if it's blown.
2. Inspect the wiring: Trace the wiring from the washer switch (usually on the steering column) to the washer pump. Look for any broken, frayed, or disconnected wires. Pay close attention to the connections at the switch, pump, and any relays involved. A visual inspection might reveal corrosion or damage.
3. Test the washer switch: With a multimeter (if you have one), check the continuity of the switch when it's activated. This will confirm if the switch is sending a signal. If you don't have a multimeter, you can try bypassing the switch (carefully!) with a jumper wire to see if the pump operates. Caution: Only do this with the ignition OFF and the battery negative terminal disconnected to avoid shorts.
4. Check for power at the pump: With the ignition ON and the washer switch activated, use a multimeter to check for voltage at the pump's wiring connector. If there's no voltage, the problem is before the pump (wiring, switch, or fuse). If there *is* voltage and the pump still doesn't work, you might have a faulty pump (despite having replaced it – maybe a bad replacement?).
5. Relay (if applicable): Some systems use a relay to control the washer pump. Locate the relay (if your car has one; consult the owner's manual) and test it or swap it with a known good relay of the same type.
If you've checked all of these and still have no luck, it's possible there's a more complex electrical issue (like a faulty ground connection) requiring a more in-depth electrical diagnostic. At that point, it may be best to consult a mechanic.
