1988 Sun Lite

where is your water fill, could it be an external tank level that is handy to the fill port? just guessing but who knows.

Steve

DIY battery monitor or ramp charger for a Illudium PU-36 space modulator....
Or something just to mess with the next guy.....

The box-Pretty sure something previous owner added




The box 'looks' like it has a row of LEDS, the switch 'looks' like a momentary switch... which leads me to think (or just a WAG), a monitor that is briefly powered by pushing the switch. What it monitors or why unknown. Looking inside possibly see where the wires go might give a clue to its intended function.
The wires appear 14ga or larger so tend to lean toward power?
Though I would suspect that year camper it doesnt have a battery?
Being outside possibly connected inline on the umbilical cord to check truck battery? Again just guesses...

Hi and welcome! Enjoy your new camper!
I can not help you with a manual, except that if it exists, it may not answer your questions. The usage of the individual appliances is usually described in individual manuals, and the camper manuals tend to be a bit generic. You may also try a forum search, or a google search.
This is a 1993 Lance manual; it may be able to answer some questions (Lance have all manuals online going back to 1993): https://www.lancecamper.com/docs/1993-owners-manual.pdf

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