Owners manual for 1987 pilgrim truck camper model number 636 sb

The electrical should be pretty simple on a camper from that era.

You need to find the converter, which is also the electrical distribution center for the whole camper. It will be behind a plastic panel on a cabinet. Under the panel will be 2-3 circuit breakers and a row of automotive fuses. Converters are generic.

Then find the battery box. In an older camper it is probably underneath a seat in the dinette. It may also be under an external hatch. There will be a plastic box with a vent to the outside. If you just got this camper and nothing is working the battery is probably stone cold dead. At the very least disconnect it and tape up the bare end of the + cable, but ideally, install a new battery. A jump starter pack will work for testing as well. With a live 12V battery connected the interior lights should work when you turn them on.

Finally, locate the "shore power" cord. It will be in a small round porthole on the outside. The cord will have an odd plug you've probably never seen before if this is your first RV, but it's just 110V and you can plug it into a normal wall outlet with an adapter. Just don't try to run the air conditioner. With this plugged in everything in the camper should work, 110V plugs and 12V appliances.