I have a Whirlpool duet dryer that will power on but when I push start button it beeps and clicks at me. Did diagnostic test which showed code 88 and then opened door and code changed to 3E. Any idea what to do now?

That is actually the code you are supposed to get when you open the door in diagnostic mode. It indicates that the door is open and tests the door switch. There are a bunch of little tests you can run in that mode, most of them just check the switches and LEDs so it is minimally useful.

I presume that you have retrieved the service manual from the top section of the dryer (mine was in the top part of the dryer attached to the right hand side). There are some really useful diagnostics in there that might help with your beep and click issue (you'll need an OHM Meter for many of them).

If you hear the click and you hear a motor humming it might just be that you need to replace the belt. The heater won't come on unless the drum is rotating (centrifugal switch). There should be a narrow, stiff little belt that goes around the drum, right in the center. If you cannot see it with the top off then you need to replace it. I've never done that but my guess is that the hardest part is moving the drum in a way so that you can get the belt around it (ye haw, lasso that baby).

If not the belt then something in the motor circuit is bad. The diagnostics also tell you how to measure the coils on the motor to see if the motor is bad. The only other logical thing is that some other system is keeping the logic from turning the motor on, a connector has come loose or some such thing. The schematic should help track down where in that circuit things are bad. There is probably a section in the service manual on troubleshooting this but I spent all my time recently on dryer not heating problems.

Good Luck!