Answer to "Fan stays on when door is open, door switches test good"Check one of the switches at the top, usually goes bad. Open the door, remove the top molding (screws), remove the panel on the right (careful with wires). Remove carefully the Switch holder and check the top switch continuity. If it’s bad, replace. You can buy them on Amazon for about $10 to $12. Reassemble, test and see if microwave works normal. I have recurring same issue and problem goes away replacing the switch. Hope the explanation helps. Good Luck.
Answer to "Fan stays on when door is open, door switches test good"Hi Adam - I had the same issue and my Microwave is GE Profile. The Overhead Fan was TURNING ON, when I closed the door. I kept it ON for an hour and NEVER TURNED OFF. After my investigation and following your directions, the TOP Door Micro Switch (NO) was FAULTY (seems got HOT, Melted a BIT, and Went Bad) and verified/confirmed with Multi Meter too. I replaced the BAD Switch with a NEW ONE. PROBLEM FIXED and WORKS NORMAL. It was just a bit time consuming process and your LOGIC WORKED. just wanted to share and THANKS A LOT and APPRECIATE your SUGGESTION. By the way, even though I am a mechanical engineer, unable figure it out why OVERHEAT FAN COMES ON. EXCELLENT INFORMATION, LOGIC, SUGGESTION and THANKS A LOT. Ravi