You did not give your model.
On my Precept 35UN I must unhook the safety belt device first. Then I turn on the key switch and push up or down button to raise/lower the bunk. I have to put main slide out in order to access the switches. The slide is not part of the controls, I just can't get to switches with slide in the way.
If you don't disconnect the safety belt, the switches will be dead. The belt is a backup device to prevent bunk from coming down while driving.
What you don't see is the buckle half of the belt contains a switch that opens the circuit to key switch when buckled.
2015 Jayco Precept 35UN
Towing JEEP TJ with Roadmaster plates and bar w/Blue Ox Patriot brake
an Aluma low bed trailer with HD Road King and/or Polaris RZR onboard