Microwave fan not running - GE JVM1650 1000 Watts Microwave Oven

This is normal. Kenmore microwaves will stay running with fan and light on for a short time after food is cooked. The reason is to air out the microwave after cooking. Things like pop corn, Bacon etc. have strong smells after cooking. The ventilation helps to remove odors.

Yes. Faulty door interlock switches.
Replace the door switches with the correct ones.

These above range microwaves "hoods" automatically turn on a cooling fan even when the microwave is not in use. If you read the manuals you will see warnings about the fans automatically starting. Even when the microwave is not in use opening the door likely interrupts the power to the automatic cooling fan.

when microwave is running the fan sounds like it is grinding

If it is only when he exhaust fan is on, something is in the fan. Remove the grill and investigate. If it is from the Magnatron fan you will have to remove the front panel.
Eric

It is overheating, but what I need to know does the fan work when microwave is running and at some point the fan cuts off even with the microwave still running? if so it may be that the fan is kicking out and then microwave runs and gets hot.

beeping how to mute

There are two different fans in this model, as with almost all over the range microwaves.

One is the hood vent exhaust fan, which you can turn on and off at will, and which should always be on when cooking on the stove top.

This fan does not automatically come on when you cook with the microwave.

The fan which should always be on (automatically) when you are microwaving is the internal magnetron cooling fan.

If the cooling fan fails, the magnetron can overheat and the thermal cutout (TCO) / thermostat will open, killing the power to the oven. Ideally, this protects the magnetron from being destroyed.

If the thermal device is a thermostat, it will reset when it cools down, and the oven will work.

If the thermal device is a true thermal fuse, it is a one-time device and if it blows, it will have to be replaced.

If your cooling fan is bad, it needs to be replaced before using the microwave.

You can usually find helpful exploded view diagrams and order parts by entering your full model number here.

There should also be a "mini-manual" hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting & testing.

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

SOME BUT NOT ALL OVENS HAVE RELAYS TO TURN THINGS ON AND OFF CHECK THE OVEN TO SEE IF YOU HAVE ANY
RELAYS AND SEE WHAT THEY DO.

the fan may be clean, may be fan bush struck thats why fan running not properly, check the internally inside the microwave oven , you should carefull inside micro wave oven very high voltage .