On an F53 it's usually above the brake pedal or just to the left of the pedal. The wires may be just taped together with no plug. Mine were taped together and once the tape was removed the colored wires were visible and only 2 were labeled with a white sticker indicating brake controller and power. Usually on the earlier F53's no easy direct plug in piece was installed, just the proper colored wires taped together and tucked up out of the way. Hope this helps.
Retired and enjoying it!
2005 Coachmen Aurora 3380 MBS Class A F53 V10 Banks Power System.
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