In this forum topic, the tech was working on a dryer that shut down a few minutes into a cycle:

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Problem Statement (State what is the appliance doing that it should not be doing, and what it's not doing that it should be doing.): The dryer would start but then after a couple of minutes would stop, no matter what setting.

 

What diagnostics have you already done?: Tried putting it into diagnosis but won't go into it.

 

In addition to having trouble putting the unit into diagnostic mode, there were some other odd symptoms too:

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The dryer will shut down with in about 10 to 20 seconds, it will start up again when I push the selector switch to power on again. It will run without shutting down if the selector switch is on the refresh cycle and it also has heat in that mode. Thanks

I think it did beep when I turned it on. I think she did say it beeped when she when she wasn't using it.

Normally, you would suspect the thermal overload in the case of a motor shutting down shortly into a cycle. However, the other odd symptoms clued Brother igloo into the true cause:

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That would be the selector switch fault. It beeps randomly and does not beep every time you change position on the dial. It has a little circuit board on it. It makes and breaks a connection randomly for some reason. Common on these. The dryer and washer switches are identical. You can swap it to test, if you want. 

The selector switch in this model is a little electronic variable resistor, and it's a common fail for this model. igloo even provided some pictures of one of these switches taken apart so you can see the guts.

Most likely, those traces on the circuit board are getting too scored by the arm over time, creating the issue.