A 2007 T276SR, that is a nice camper. Congrats
On the 7 wire cable, here is a better quality one. I go for the Bargmen or other good brand name, the quality and the wire gauge is a better. The red and white are 10 awg, the blue is 12 awg, and the rest at 14 awg.
Cheaper off brands ones are not all that heavy a wire gauge and the molded plug does not work right in the truck. You can hunt for that Bargmen part number elsewhere to maybe be cheaper. https://www.amazon.com/Bargman-Molde..._df_B007V4W77W
But, before buying that cable, make sure 8 foot long is long enough. They do make a 10 foot one.
Now on the junction box, buying an exact replacement I have not found one, nor if I was going to replace it, actually buy the exact same one.
That junction box has 6 tiny evil screws that get dirt jammed down in the long deep hole and the screws rust and jam up in the plastic breaking off the screw jammed in the plastic. The 2004 to 2007 models I know used the same box. The 2003's may be a mixture.
Have you taken the cover off already? If not, I have some maybe better ways to have more favorable odds getting the screws out. And if you break the screws or the post inside the box, I have fixed several of them. As long as the cover and the box is intact, there are ways to deal with the screws and repair them. Let me know what you need help with on the existing box.
If the entire box is toast, then the hunt starts for a replacement. They do sell small plastic junction boxes with gasketed plastics covers. It may not be the exact same size, but big enough to house the 2 circuit breakers and the wire junction's and still fit on the A frame header. If it comes to this, let me know that too, I can help the hunt. Sooner or later I will need to buy one. The last dozen of them I had to have apart I was able to repair the broken off screw issues so I did not have to buy a new one yet.
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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