How to Replace 3387134 Dryer Cycling Thermostat on Whirlpool & Maytag Dryers — Step-by-Step

Your Whirlpool dryer runs, but the clothes come out cold. Or maybe it's the opposite — the heat won't shut off, and you're pulling out scorching hot towels that could start a fire. Both issues point to the same culprit: a failed cycling thermostat. This small part controls when your heating element turns on and off to maintain the right temperature. When it fails, your dryer either won't heat at all or overheats dangerously.

The 3387134 cycling thermostat is one of the most frequently replaced parts on Whirlpool, Kenmore, Maytag, KitchenAid, Roper, and Amana dryers. It's mounted on the blower housing and cycles the heat on and off based on air temperature. The good news? You can replace it yourself in about 45 minutes with basic tools.

What You Need Before Starting

Grab these tools before you pull the dryer out:

• ¼-inch nutdriver
• Phillips screwdriver
• Flathead screwdriver
• Work gloves (the metal edges are sharp)
• Flashlight or headlamp

Estimated repair time: 30-60 minutes

Difficulty level: Easy — perfect first dryer repair

Safety First

Unplug the dryer completely before you start. If it's hardwired, flip the breaker off. Here's something critical that one repair tech learned the hard way: even if you've replaced the heating element and it has continuity, check your breaker box. A shorted heating element can damage the breaker itself, causing you to lose one leg of the 240V circuit. Your drum will spin, but you'll get zero heat. Save yourself hours of frustration — confirm you're getting full 240V power at the outlet before you start replacing parts.

Step 1: Access the Dryer Cabinet

Pull the dryer away from the wall to give yourself room. For most Whirlpool and Maytag models like the WED5000DW2 or MEDC215EW1, you'll remove the front panel. Pop off the top panel first by releasing the clips at the corners — slide a putty knife between the top and cabinet, then lift up and forward. Remove the two screws holding the front panel (they're inside the door opening at the top). Disconnect the door switch wires, then lift the panel off.

Step 2: Locate the Cycling Thermostat

The cycling thermostat is mounted on the blower housing — that's the big metal box on the front lower section where the lint filter sits. It's a small disc-shaped component about the size of a quarter, held in place with two screws or clips. On models like the WED9200SQ0 or MDE9206AYW, it's right next to the high-limit thermostat (which looks identical but serves a different function). Don't mix them up.

Step 3: Remove the Failed Thermostat

Use your ¼-inch nutdriver to remove the two mounting screws. The thermostat is pressed against the blower housing with a bracket. Pull the wire terminals straight off — they're push-on connectors, no tools needed. If they're stuck, use needle-nose pliers to wiggle them loose. Don't yank on the wires themselves. Take a quick photo of the wire orientation with your phone before disconnecting.

Step 4: Install the New 3387134 Thermostat

Position the new cycling thermostat against the blower housing exactly where the old one sat. The metal disc needs direct contact with the housing to sense temperature accurately. Thread in both mounting screws and tighten them snug, but don't overtighten — you'll crack the plastic housing. Push the wire terminals onto the new thermostat. They only fit one way, but double-check your photo to be sure.

Step 5: Reassemble and Test

Reinstall the front panel in reverse order. Reconnect the door switch wires, align the bottom clips, then secure the top screws. Slide the top panel back until it clicks. Push the dryer back into position, plug it in, and run a test cycle on high heat with damp towels. Within 5-10 minutes, you should feel hot air coming from the vent. Let it run for 15 minutes — the heat should cycle on and off, not stay constant.

Testing After Installation

Run the dryer on timed dry for 20 minutes. Open the door halfway through and feel the air — it should be hot but not painfully so. If the heat never comes on, you might have a blown thermal fuse (common when thermostats fail). If the heat won't shut off and the drum stops spinning but heat continues, you've got the wrong thermostat or faulty wiring. On models like the WED4815EW or MEDC400VW0, a cycling thermostat failure often happens alongside a clogged vent, so clean your ductwork while you're at it.

Frequently Asked Questions

How do I know if my cycling thermostat is bad or if it's the thermal fuse?

Test with a multimeter. The cycling thermostat should show continuity when cold and open (no continuity) when heated. The thermal fuse is a one-time safety device — if it's blown, it'll show no continuity ever. If your dryer won't heat at all, test the fuse first. If it runs hot constantly, suspect the thermostat.

Will a bad cycling thermostat cause my dryer timer to malfunction?

Yes, indirectly. If the thermostat fails in the open position, the dryer never reaches temperature, so the automatic cycle never advances. Your timer seems stuck because the moisture sensor or auto-dry logic is waiting for heat that never comes. Replace the thermostat first before blaming the timer.

Can I use WP3387134 or 3387135 instead of 3387134?

Yes. The 3387134 is the manufacturer part number, while WP3387134 is the updated Whirlpool version. Parts 3387135 and 3387139 are also direct replacements with identical specs. AP6008270 is the associated part number. They're all interchangeable on compatible models like the NED4655EW, WED7400XW0, or AED4475TQ0.