A relay kit, like I build, will solve the heat problem in your system. The OEM system only triggers relays and carries very little load, less than .25 amps vs 15+ with the stock set up.
The breaker in the switch is tripping because the system has resistance somewhere that is building heat. The stock system is barely adequate to fire a set of lights, bean counters at their best!
There are plenty of solutions out there, some are much better design, materials and construction than others. Good luck with whatever you choose.