How to disable the sleep switch

I am attempting to keep a MacBook Pro 15" Retina Mid 2014 from going to sleep.

The computer will be operating in clamshell mode. But, I want to prevent it from sleeping if power is lost.

I can either used clamshell mode and live with the instant sleep induced from power failure or close it and disable the sleep switch so that it does not go into clamshell mode.

I want to see how to disable the sleep switch. I know older models the sleep switch was on a sub component that could be unplugged.