Microwave fan goes on by itself without burners being on or used

I always recommend that you use the vent fan whenever you're cooking on the stove top to keep heat, steam, and grease out of the controls and door panels.

The door switches are more than likely the problem, one or two will need to be replaced, I recommend a professional.

It could be that the fan button is sticking or a contact has welded itself closed therefore its getting power all the time.

You are tripping a high limit switch which means the cooling fan is busted or the microwave is installed to close to something. That or your door interlock switches are sticking.

Please note that FixYa is not currently notifying us Experts when Clarification Requests are answered.

So please post a NEW question, and please include your brand name and the full model number from the tag in or on the unit, as well as the answers to these questions:

Which fan is it?

The internal cooling fan, which comes on automatically whenever the unit is microwaving?

Or the hood vent exhaust fan which you can turn on and off manually?

Or the convection fan, if it is a convection model?

When is it coming on?

Is it coming on whenever you cook on the stove top?

Thanks!

Direct spraying of cleaners on the keypad and steam from the cooktop can short the keypad.

Luckily, it dried out. Sometimes it doesn't, and the keypad has to be replaced.

I always recommend that you spray non-ammonia cleaner on a soft cloth (not a paper towel which can scratch) and gently wipe the keypad.

And I always recommend that you use the vent fan when cooking on the stove top to keep heat, steam, and grease out of the controls.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

The only thing I did was to unplugged; turn off all the burners; and let everything cool off. I guess I can't have all the burners on at one time since the microwave is 13" from the burners......and from what I read "microwaves placed over the range" should be at least 30" from the burners...thank you, Rose66

This light failure often occurs when a bulb goes out and the filament shorts, or when the bulbs are removed or installed without first unplugging the oven from the power line. Either can cause such a failure on the controller.

This can often also affect the exhaust fan operation, too. The lights and fan can be inoperable or stuck on too.

Details of our service and critical safety information and disassembly information is at our site, linked here on Fixya:
http://tinyurl.com/yzjozk

The problem is almost certainly on the control panel, which we repair nationwide for $39.95 postpaid.

This light failure often occurs when a bulb goes out and the filament shorts, or when the bulbs are removed or installed without first unplugging the oven from the power line. Either can cause such a failure on the controller.

This often can affect the exhaust fan operation, too. The lights and fan can be inopoerable or stuck on.

If you or a friend decide to look into it, we have critical safety information, info on door switch diagnosis and replacement, and

disassembly information at our site, linked here on Fixya: http://tinyurl.com/yzjozk