Air conditioner works on high but not on low

[ncrenshaw33]

Hey guys I was running my ac unit on the argosy tonight and it quit working on low setting. The fan doesn't come on and I can't hear the condenser kick on. But on high everything comes on. It is a Armstrong unit and was just wondering if anyone had any idea what could cause this? Thanks

[overlander63]

A bad selector switch will cause that.

[ncrenshaw33]

Thanks, is this a part that can be ordered and if so where may I go about ordering or finding this selector switch?