If your dishwasher runs a full cycle but the dishes come out dry and hot, water never entered the tub. That’s a different problem than a machine that won’t drain or one that leaks, and the fix is usually in one of three places: the water inlet valve, the float switch, or the door latch assembly.
Most Likely Cause: The Inlet Valve
The water inlet valve is a solenoid-operated valve, usually at the bottom left or right of the machine behind the lower access panel, where the household supply line connects. When the dishwasher calls for water, the control board sends power to that solenoid, the valve opens, and water flows in. When the valve fails, nothing happens and the machine runs dry.
Inlet valve failure is the most common cause of this symptom. The valve can fail mechanically (the plunger corrodes or seizes), electrically (the solenoid coil burns out), or the screen filter inside clogs with mineral scale. Hard water in much of the Bay Area accelerates that last one.
A tech confirms the valve diagnosis by measuring voltage at it during a fill cycle. Power present but no water flow means the valve is bad. Power absent means the issue is upstream, either the control board, a wiring harness connection, or one of the safety switches below. Getting that part of the diagnosis wrong means replacing a valve that didn’t need replacing.
Second: The Float Switch
Inside the tub, near the bottom, there’s a small plastic float, usually a dome or cylinder. It rises with the water level and trips a switch to stop filling. If it gets stuck in the raised position (food debris, buildup, or a warped float), the machine thinks the tub is already full and never opens the inlet valve.
This one is worth checking yourself. Open the dishwasher, find the float assembly near the bottom of the tub, and lift it manually. It should move freely with no sticking. Clean any debris from around the base. If it was stuck and you free it, run a test cycle.
Third: The Door Latch
Dishwashers won’t fill if the door latch isn’t fully engaged. The door switch is a safety interlock, and on older machines the latch can wear so it feels closed but isn’t making full contact.
Close the door firmly and listen for a solid click. If the latch feels loose or the door has any play, that could be your problem.
Other Causes Worth Knowing
Less commonly, the supply valve under the sink gets partially closed (often after plumbing work), the fill hose is kinked, or the control board has a failed relay. On older machines with electromechanical controls, a faulty timer can skip the fill stage entirely.
Low pressure is another factor. Most dishwashers need at least 20 PSI at the inlet to fill properly.
What You Can Check Yourself
Three safe checks before calling:
- Confirm the supply valve under the sink is fully open.
- Lift the float assembly and check that it moves freely. Clean around the base if there’s debris.
- Close the door and listen for a clear latch click.
Stop there. Everything past that point involves removing access panels, testing live electrical connections at the valve, or disconnecting the water supply in a tight space. Misdiagnosing it also costs you parts and labor on the wrong fix.
Why a Tech Makes More Sense Here
The full diagnosis is one visit. A tech confirms water supply, checks the latch and float, runs a fill cycle with test equipment on the valve, and determines whether the problem is the valve itself or something upstream like the control board. That sequence matters because a valve swap won’t fix a control board issue.
On most mid-range dishwashers, an inlet valve repair is worth doing. On an older machine with other wear, it’s worth asking the tech whether repair or replacement makes more sense before ordering parts.
If you’re in the Tri-Valley or East Bay, give us a call or book at adriumservice.com. We’ll get you on the schedule fast, often same or next day when we can.