Not sure which vehicle it was, but I had a similar issue, On the brake pedal there were 2 switches, one to turn the brake lights on and a second switch to deactivate the cruise control, with wear, the cruise switch thought that the brake pedal was depressed, only a minute adjustment. Simplest was would be to lift the brake pedal with your toe and see If the cruise control works. If that is the problem, then an adjustment needs to be made at the switch/pedal area, if not, sorry.
Another issue I had with our E450 was the remote operation of the power door locks not working, switches on inside of door worked but not the fobs. I was told to reboot, reset the remote module, but couldn't locate the module or correct fuse, finally disconnected the Ford battery for about 1/2 hour. When I reconnected the battery the remote key fobs worked.
Ken
2006 Winnebago Outlook 29B E-450.
2012 Honda CR-V AWD
Blue Ox Aventa LX tow bar and Brake Buddy Vantage.