Whirlpool model # XXXXX 1160XSQ-1 (April, 2007)
Most microwave door switches can be tested for continuity to see if the switch has failed. This can "fool" you sometimes. This switch looks fine, tested fine with an ohm meter and even made the "click" noise ok when we pressed on the actuator button.
Once we opened up the switch, it became clear this switch's contacts where being overheated and failing = new switch time.
This switch "looked" ok, "checked" ok with an ohm meter...but as you can see...it is not ok. one out of the three is bad on yours. normally replacing all three is the best way to go,
you can get these @ http://www.repairclinic.com/SSPartDetail.aspx?s=t-MH+1160XSQ-1-%3d%3dei1472224&PartID=1472224 two will have continuity when the door is open and one when the door is closed, hope this helps.
How do you get in to replace the switches? Where on the unit do the switches go?