^ +1. If the switch won't reset with the pushbutton, the magnet has probably gotten weak - it's time for a new one.
One of those things you hope you never need, but will be glad it's there when the occasion calls for it.
1989 F150 XLT standard-cab shortbed 4x4, 5.0L, AOD, 3.55 gears, manual hubs, 31x10.50 tires, 218K miles. Repainted Oct09. SOLD - Jan2015
2014 F150 XLT standard-cab shortbed 4x4, 5.0L, 6-speed auto, 3.55 gears, auto hubs, locking diff, trailer pkg, 3K miles.