Since you have a 2004 model, I happen to have pics of that vintage that may help.
Before you do the items below, I agree if you have a volt meter, make sure something is wrong with not getting any 12 volt power at the power converter. If you need help on how to do this, let us know and we will explain that. Assuming there is not 12 volt power at the converter then,
What you are describing sounds like the 30 amp "circuit breaker" that is mounted in black plastic junction box on the front frame of the camper is corroded and no longer working. This is not a fuse inside the converter inside the camper.
This is what it looks like inside that junction box. This is from my 2004 T310SR but I also had a 2004 T2499 camper. The box we are talking about is on the front camper frame next to the battery disconnect switch. See here
Inside that box is a self resetting 30 amp circuit breaker. See here with the cover off. These are from the 2004 T2499
Here is a pic of the side of the breaker, this is from my T310SR but is the same breaker as the T2499 and yours
Odds are high that breaker has gone bad. Water can get in and corrode them. You can buy them at most auto parts stores as they use these on cars/trucks all the time. Our very good friend the late Kitty, had this exact issue on her T2499. This thread. http://www.sunlineclub.com/forums/f7...ower-8988.html
The other folks were talking about the same 30 amp thing, but on the older campers they had a fuse to do this. And that fuse box was in many places on the older campers. In 2004 model year I believe is when this box came and the auto reset circuit breakers along with the big red battery disconnect.
Now to the hard part, getting in that box.... I have nick named the screws that hold that cover on as "evil screws"... They are tiny Philips screws buried about 1" inside the plastic box. They are set back from the front. Most times dirt fills the holes and you cannot tell what is in there.
Get a small drill bit and by hand, twist it in to drill out the dirt. Do not use a drill motor, do it by hand. Eventually you will find the screw. Blow out what dirt you can and get a small Philips screw driver and a small hammer. We are talking tiny screw driver. Gently tap the screw driver when engaged in the star of the Phillips screw to deep seat the screw driver and force out the dirt.
Then press in hard on the handle of the screw driver and try to get the screw out. You have to press in hard as you unscrew to not strip out the Phillips star point. And it fights you most all the way out.
There are 6 of little buggers to get out. If luck is on your side, all 6 will come out and not break the box in the process. And if you do not break the box in the process... Then I suggest this upgrade when you go to put it back together.
Buy qty 6, stainless no 6 or no 8 sheet metal screws 1" long. They will only bite in about 1/4" but they will hold. Do not over tighten. Then those screws are on the outside like this and no more evil screws buried down in deep. I used no. 8's
Also, using 3M 33 electrical tape, wrap around the cover split line to the back mounted box to seal out water in the future.
Looks like this
here is the 3M 33 electrical tape
Hope this helps.