I have a 1982 15.5 SB, I believe virtually identical to your rig. I would be glad to answer any specific questions. My rig can be seen under files/othersunline files/preparing a sunline.
I have done a lot of work on mine except for the air conditioner which we don't have, other than that I should be able to help.
Switches.
All the lights have switches.
The trickiest is the first switch on the left as you come in the door. That controls the outside light. It's tricky because the outside light also has a switch behind its handle, a small pushbutton.
The next switch as you come in is turns on the water pump. The water pump is located behind the door below these switches.
Continuing to the left is the stove vent fan switch.
The next switch after that is the thermostat. You're may different than mine since you have an airconditioner. However my thermostat has a white slide switch that enables the gas heater located below the refrigerator.
If you're heater is like mine, it has a pilot switch/valve and a push button ignitor switch. There should be instructions behind the heater cover. If they're not there I'll send you a copy of mine.
Somewhere you have a switch for the airconditioner.
There are two switches I skipped, they are your breakers, located under the hanging closet. One breaker is probably used exclusively for your air conditioner, the other for all other AC outlets and you converter.
My rig came with only one breaker since I don't have an air. If you don't have air you probably have one breaker and a 15 amp cord.
The only other switch I know of is the safety switch on the tongue of the trailer used to activate the trailer brakes in a breakaway situation.
The converter is under the rear couch. There should be a fuse block there that distributes 12 volts through out the trailer. I replaced my converter so I can't tell you what every fuse is for. You can find out by removing one at a time and seeing what doesn't work.
Hope that helps and don't hesitate to ask me anything. I don't mind if you use my personal email -
normacs@aol.com
Norm