How to Make a Bypass Dongle for Washer Lid and Dryer Door Switches (For Testing)

If you’re a service technician — or a serious DIY-er — you’ve run into this call a hundred times: customer says the washer fills, agitates, then quits cold at the spin cycle. Or the dryer hums but won’t tumble. Nine times out of ten you’re looking at a failed lid switch on the washer or a bad door switch on the dryer. The fastest way to confirm it before pulling the cabinet apart is to bypass the switch with a test dongle and see if the machine kicks into gear.

This guide shows you how to make three small bypass dongles that live in your service kit and pay for themselves on the first call: one for dryer door switches, one for small-style washer lid switches, and one double-ended dongle that handles both the small and large styles of washer lid switch from one tool.

I’m Chip Knowles. I run Harper & Knowles Washing Machine and Dryer Repair in Oakdale, Louisiana. Watch the full build below.

Watch the full build

⚠️ Read this before you build anything

These dongles are diagnostic tools for service technicians. They are not a fix. They are not something you leave installed in a customer’s machine.

The lid switch on a washer and the door switch on a dryer exist for one reason: to stop the basket or drum from spinning when the lid or door is open. A spinning basket grabs clothes, hair, hands, and small children. Permanently bypassing these switches is how people get seriously hurt.

Three rules I follow every time:

Test only. Plug the dongle in to confirm the suspect switch is the actual problem. Once confirmed, install a new switch and remove the dongle.
Never leave the dongle installed. Especially not in a household with kids.
If a customer asks you to “just splice the wires and bypass it” as a permanent fix, decline. Sell them the replacement switch. It’s a $15 part on most machines.

That out of the way — here’s how to build the dongles.

What you need

Every tool and part below is on my Amazon storefront — one-stop spot to grab what you need: amazon.com/shop/harperknowleswasheranddryerrepair

A handful of old, defective lid switches (the kind you’d normally throw out after a repair) — you’ll cut the plug end off and reuse it
A few old dryer door switches with their plugs — same idea
Butt splicers — I use the Harbor Freight ones; they fit two wires per end and crimp with regular pliers — Buy on Amazon
Wire strippers / pliers — Buy on Amazon
Band saw or hacksaw — for opening the plastic housing on some switch styles (optional, only needed for one type)
Heat shrink tubing (optional but cleaner) — Buy on Amazon

The whole project costs maybe $5 in butt splicers if you’re salvaging the switch plugs from machines you’ve already pulled apart.

Background: the two dryer door switch styles

Most American dryer door switches come in two flavors, both interchangeable in terms of how you bypass them:

Older flapper style — the door pushes a hinged flap that makes contact between two wires. Plugs into the upper right corner of most dryers.
Newer plug style — same idea, different shape. Often has a third wire that powers the drum light. The plug has a pointed pin on one side and a flat side on the other so it only fits one way.

For the bypass, all you care about is connecting the two main wires that complete the circuit. If the switch has a third wire (the light wire — usually the one in the middle of a three-pin plug), you can connect all three together if you want the light to come on during the test; otherwise just bridge the two outer wires and ignore the third.

Building the dryer door switch bypass dongle

Find a defective dryer door switch with its plug intact. The switch itself can be dead — you only need the plug end and a couple inches of wire.
Cut the plug off about two to three inches behind the connector. Toss the rest.
Strip the wire ends. You should have two wires (or three if it’s a light-equipped switch).
Connect the two main wires together with a butt splicer. Just twist them into one end of the splicer, crimp with pliers, done. If you have a third light wire, you can throw it into the splice too — the splicers fit two wires per side.
Slide heat shrink over the splice and hit it with a lighter or heat gun. Optional but cleaner.

That’s it. Plug this dongle into the dryer’s door switch harness in place of the actual switch and the machine will think the door is closed. Useful when the customer’s switch is intermittent and you want to confirm it before pulling the front panel.

Background: the three washer lid switch styles

Washer lid switches come in more varieties than dryer door switches. The ones you’ll see most often:

Plug-style with rod actuator — a metal rod hangs off the lid and drops into a slot when the lid closes. Plugs into a connector on the washer side of the cabinet.
Microswitch style — a pin on the lid pushes a lever on the switch.
Underneath-the-lid style — fits under the lid, gets pushed by a downward pin.

Within those, you’ll see two physical sizes — a “large” plug and a “small” plug. We’re going to build one double-ended dongle that handles both.

Building the single-ended washer lid switch bypass dongle

If you only deal with one size of switch in your area, the build is identical to the dryer dongle:

Cut the plug off a defective lid switch with two or three inches of wire attached.
Strip the two main wires (the green ground wire isn’t needed for the bypass — cut it off close to the plug).
Splice the two power wires together with a butt splicer.
Heat shrink if you want it clean.

Plug it into the machine in place of the lid switch and the spin cycle will run with the lid open. Stand back. Do not put your hand near the basket.

Building the double-ended washer lid switch bypass dongle (one tool, both sizes)

This is the build that pays for itself on a service call when you don’t know which size switch the customer’s machine takes until you’re standing in front of it.

Find two defective lid switches — one large-plug style and one small-plug style.
Cut both plug ends off with about two to three inches of wire each.
Cut the green ground wires off close to each plug. Not needed.
You now have two plug ends, each with two wires hanging out.
Splice them end to end. Take the two wires from one plug and the two wires from the other plug and combine them through two butt splicers — wire 1 of plug A to wire 1 of plug B, wire 2 of plug A to wire 2 of plug B.
You now have a single tool with a small plug on one end and a large plug on the other. Plug whichever end fits the customer’s machine into the harness; the dongle completes the circuit either way.

Heat shrink or electrical tape over the splices makes it look professional and keeps the splices from getting bent up in the toolbox.

When you’d actually use these dongles

Real-world example: customer calls and says “my washing machine fills, agitates, sits there — but it won’t drain or spin. It just stops.” Nine out of ten times, that’s the lid switch failing. You don’t need to disassemble the machine to confirm it. Unplug the lid switch harness, plug your dongle in, run the spin cycle. If it spins, the lid switch is bad — order the part, swap it in, you’re out the door in 30 minutes.

Without the dongle, you’re pulling the cabinet to physically inspect the switch, then re-pulling it to install the new one. The dongle saves you the first trip inside the machine.

The customer who already bypassed it (you’ll see this)

A common find on a service call: the customer (or someone before you) cut the two lid-switch wires and twisted them together to “fix” the no-spin problem permanently. Now you’re standing in front of a washer that spins with the lid open and a customer who doesn’t understand why that’s dangerous.

Two moves: explain why the bypass has to come out, and quote them a new lid switch plus the labor to re-wire the harness correctly. Most customers will agree once they realize it’s a $15 part on a $400 machine and they’ve got grandkids in the house.

Need someone to fix this for you?

If you’re in central Louisiana — Oakdale, Oberlin , Glenmora, Elizabeth, Pitkin, Pine Prairie— and your washer or dryer is acting up, give Harper & Knowles a call at (337) 831-6757. We’ll diagnose the actual problem, replace the right part, and leave the safety switches working the way the manufacturer intended.