2021 Fleetwood Discovery LXE 40 M

Can anyone tell me where the receptacle is to plug in 110V AC to the engine pre heat - AKA Block Heater? Freightliner has informed me that a block heater came with the chassis but wasn't sure where the wiring would be. 

Do I nee to buy a cord that connects to the Block Heater wiring harness that has the 110V receptacle on the other end?

EDIT: I contacted REV group with this same question. They quickly responded that the block heater should already be plugged into a receptacle under the sink in the rear bathroom. The control switch is on the Firefly control panel. Shout out to REV Group. They have been great at answering my questions.

Thanks

Doug