WTW4950HW3 Pressure Switch – What the Part Does and How to Replace It
Need the replacement part? Search your model number at for guaranteed fit and fast free shipping.
Understanding the Problem
Brief explanation: The pressure switch (also called the water level switch or air pressure sensor) tells the washer's control board how full the tub is by sensing air pressure in a small hose connected to the tub. If it fails, the washer may overfill, underfill, not advance cycles, or show error codes. Step-by-step diagnostic and repair steps: 1. Observe symptoms and error codes: Look for error codes (if any), erratic fill levels, washer stops mid-cycle, or won’t detect water level. 2. Inspect the air hose: Unplug the washer. Remove the top or back panel to access the pressure hose (a small clear or black flexible tube running from the tub/plenum to the pressure switch). Check for kinks, pinches, clogs, or disconnections. Remove the hose and blow through it — it should be clear. 3. Inspect the pressure tap at the tub: The hose connects to a small plastic nipple on the tub or pressure dome. Make sure that nipple is not clogged with lint or detergent buildup and that the hose seat is tight. 4. Listen for the switch click: With the washer powered on and a short test fill cycle (or using diagnostic mode), gently squeeze the pressure hose or blow into it while watching/hearing the pressure switch. You should hear/feel a distinct click as air pressure changes and the switch changes state. If no click, suspect the switch. 5. Electrical test with a multimeter: Disconnect power. Unplug the harness from the switch. Set a multimeter to continuity/ohms. On most pressure switches you will see continuity between common and one of the terminals at rest and it will change when pressure is applied. Refer to your machine’s wiring diagram for exact terminals. If there’s no change in continuity when you blow into the switch, the switch is faulty. 6. Voltage check (advanced): With the machine powered and in a safe diagnostic state, measure the signal voltage from the control board to the switch per the wiring diagram to confirm the board is sending/receiving signals. If the board sends proper signals but the switch doesn’t respond, replace the switch. 7. Replace the pressure switch: If the hose and fittings are good but the switch fails audible and electrical tests, replace it. Replacement steps: unplug washer, remove access panels to reach switch, label and disconnect wiring harness and hose, remove mounting screws/clips, install new switch, reconnect hose and wiring, reassemble, and run a test cycle to confirm proper operation. 8. Final test: Run a few cycles with different load sizes to confirm correct fill and cycle advancement. Safety note: Always unplug the washer (or switch off the breaker) before doing inspections or electrical tests. When testing live voltages follow safe practices and only perform live tests if you are comfortable and experienced with electrical measurements.
Common Symptoms
Washer overfills or underfills, won’t advance cycles, pauses or stops mid-cycle, inconsistent spin, or displays water-level related error codes.
Common Causes
- Clogged, pinched, or disconnected air/pressure hose
- Failed pressure switch (no internal contact change or stuck diaphragm)
- Faulty wiring or connector between switch and control board
Popular Parts That Fix This Problem
These are the most common replacement parts that fix this problem. When you're ready to order, click below to find the right part at ProsourceParts.com — just search by your appliance model number for a guaranteed fit.
Helpful Repair Tip
Quick confirmation: With the hose disconnected and the harness still attached, gently blow into the switch hose while listening for a click — if no click and no continuity change on a multimeter, replace the pressure switch.
Frequently Asked Questions
How do I test the pressure switch on my WTW4950HW3?
Unplug the washer, access the pressure switch and its hose, and inspect the hose for clogs. Reconnect power (or put the washer into diagnostics), then blow gently into the hose; you should hear/feel a click from the switch. For electrical testing, disconnect power, unplug the switch harness, and use a multimeter to check for continuity changes when you apply pressure to the switch. If the switch doesn't click and the multimeter shows no change, the switch is bad.
Can a clogged pressure hose cause the same symptoms as a bad switch?
Yes. A clogged, kinked, or loose pressure hose will prevent the switch from sensing tub pressure correctly and cause overfill/underfill or cycle problems. Always inspect and clear or replace the hose before replacing the pressure switch.
Related How-To Videos
Real DIY Repair Stories
Be the first to share your repair story!
Share Your Repair Story
Your experience helps other homeowners fix their appliances. Tell us how it went!
Can't Fix It Yourself? Find a Local Technician
It's perfectly okay to call a professional. Some repairs require specialized tools, deep teardowns, or dealing with complex systems that are better left to the pros.
Find the Right Part for Your Appliance
Don't guess — search your exact appliance model number at ProsourceParts.com to find the correct OEM compatible replacement part. They offer fast free shipping, guaranteed fit, and thousands of parts in stock.
Your Free Parts Videos
Whether your dishwasher won't drain, your dryer stopped heating, or your fridge isn't cold, we've created simple repair guides for the most common appliance problems homeowners face. Each guide explains what's going wrong, the most likely causes, and which replacement parts fix the issue. When you're ready to order, we link directly to ProsourceParts.com where you can search by model number and get the right part shipped fast.