Gear doors won't close on ground...

[Dale Campbell]

I just replaced my 2 Main gear down lock switches. They gave me a lot of problems with intermittent gear doors failing to close. I checked the resistance with a meter across both switches and found the resistance to be about 100 ohms when it should be zero. I think the inside of these little mico switches get very dirty and the contact resistance goes up until they fail. After changing these 2 switches all my gear failure problems disapeared. Dale