How to Troubleshoot & Replace Ge AP3994765 / WD21X10261 Interlock Switch

I could hear the dryer motor hum, but it would not run. There was nothing obstructing the motor from turning freely so I assumed I needed a new motor. I went ahead and ordered a new pulley switch to change out while I was in there just in case. The parts arrived faster than expected. I changed the switch first and then checked the old motor which surprisingly fired right up. Now I have to decide whether to return the new motor or keep it as a spare. 

Replaced tension arm switch 

When operating door switch, the dishwasher would work intermittently. I removed the door inner liner and checked: my model had two switches side by side. One was obviously bad: the switch button was pushed in and would not spring out. The other looked OK. I ordered two switches on a Monday and Tuesday evening they arrived. I popped them in taking about 20 minutes total and back in business. The exploded views of parts shown on the Appliance Parts Pros site is a real help in identifying parts and part numbers. 

Replaced Belt Switch/Interlock Switch after testing with Multi-meter and determined that it was bad: Removed Dryer Top Removed Front Panel, including Door Removed Dryer Drum Loosened Motor Assembly to Slide away from side of the dryer to gain access to the Belt switch Removed Belt Switch Replaced Belt Switch Reassembled Dryer Tested and dryer functioned as expected. 

Belt was good. Board was sending 110V to the motor area. On schematic I found "Idle switch". I found it on the bottom by the idler wheel lever. On the website it is called Interlock switch - took time to figure out that it is the same thing. Shorting the switch proved to me that the switch is the problem, not the motor. 

Replaced the belt interlock switch. It was a very easy repair to make as I followed the helpful videos online. Each step was clearly described and everything progressed just as shown in the video. 

After replacing the belt less than a year ago, when it broke again we started to think something may be going on with the idler pulley. Ordered a new belt and pulley wheel, only to have the belt break again the very next day. After a call to customer service explaining the situation, they replaced the belt and pulley wheel which were both under warranty, and suggested replacing the arm itself. We also had to replace the interlock switch. Parts arrived quickly. The repair itself took about an hour and a half. If you aren’t experienced with these sort of repairs I highly suggest taking pictures of all the wire connections before you start unplugging them (especially the door which HAS to be unplugged in order to slide the motor out). That turned out to be a lifesaver when putting everything back together. I ended up replacing the pulley arm which seemed to have warped a bit, but keeping the original wheel on there. The replacement wheel didn’t seem to fit as well as the original and the original showed no signs of wear. I also added a generous amount of lubricant grease (Lucas oil Red n tacky from Lowe’s) to the pulley arm where the wheel sits, as there was some there when the dryer was new. Dryer is back to work. All in all it was a easy repair if you have all the right tools (I used 4 different screwdrivers and a pair of needle nose pliers). 

Replace the interlock switch that was stuck in the closed position. Switch protects the dryer in case of the belt breaking. Followed directions on your video. Only tool needed was a screwdriver. The hardest part of the entire job was to determine the cause of the problem and obtain the correct part. 

Easy took 15 minutes You guys are amazing! 

After Diagnosing the problem to be one of the interlock switch. I decided to replace both of them. It was a really easy job that anyone can do. It did not take long at all to get the parts (2 days). I knew the part was bad because the button on top the switch was stuck in the down position. The other one would not make a clicking sound so I suspect it was going bad too. To confirm my diagnosis, I test the switch for continuity and it failed. After I installed the two new switch, the dishwasher started working again. Hope this help.