I do not know your exact TT, however most of the 12 volts system do debug the same way.
On the newer models the 12 volts circuit are split by area of the camper. My non slide camper, 2004 T2499 has 7 total circuits. They are not all on 1 circuit. I looked up the 1990 brochure and even back then the Sunlines where very nice had the same styles things in them of the year 200 and forward models. BTW which Star-ray model do you have?
And yes the fridges does operate on 12 volts if you have the normal camper ones. Even if it has an electric option, the circuit boards and gas section still run on 12 VDC.
Your lights and fridge that do not work could all be on the same circuit that is not working.
The basics to track this down is a process of elimination.
Does your TT have a chart in the Power converter box on which fuse is for which area?
The newer charts look like this.
Out of the 7 fused circuit the lights are on 3 separate fuses. Your could be similar or not. But I would think it at least has 2 lighting circuits. And the fridge cold be on one of those lighting circuits as it does not take much power.
Do you have a digi camera? If you can take a pic of the inside of your converter and the circuit tag I can help point you where to look better
First, check all fuses, if all are OK, then the next step is a process of elimination which circuit does not work.
By removing 1 fuse at a time, you can back into which one work and which does not. The does not one, we have to dig deeper into.
Tell us some more on your camper converter system and maybe we can help tell you better where to dig.
If you are going to dig, do you have a volt/ohm meter? Or a 12 volt test light?
Before I type a long windy what to do, it would help if we knew better what you had.
Hope this helps
Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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