GEProfile microwave fan problem

[frustratedSKY]

We have a GE Profile microwave with a fan that runs non-stop and the panel that opens and closes for ventilation stays stuck open. We’re unable to change the vent settings to "low" or "off" (only high, medium, and boost work). We were told it’s probably the motherboard which will cost $298 plus labor!! That’s outrageous for an appliance that was just over 2 years old (and not heavily used at all) when this problem started. We’ve had it unplugged for many months now and have used a countertop microwave to get by—can’t afford the repair at this time. Is there some way to disconnect the fan and still be able to use the other features? I never even got to try half the features, such as convection, before this problem occurred.