[FED 387]

First look at the vacuum pump area many connectors in that area that over time either corrode or work loose-Second check the brake switch which I already suggested--Third check the stalk and if necessarey pull the steering wheel should be some (5-6) small (fine)wires coiled up in there these tend to break after time the especially with the age of your MH the insulation becomes brittle--- you might have a Ford or a Dana cruise unit---next if you need to replace it cuz your vehicle is obsolete and many parts are no longer available try looking at a I believe it is a "King" cruise control unit they make aftermarket kits you might be able to make work--- Fourth --check all light bulbs any burnt out or not as bright as others might give a "false" reading and make the cruise not want to engage --- Some thoughts to look at!!! FED 387