Combines lights flicker and trip breaker

In my 2188 there is a relay and a mini breaker that looks like a fuse. I replaced the relay, didn't help, but putting a normal fuse in where the mini breaker is fixed the problem. They are both up in the headliner. It took me 6 years to discover why my work lights would cut in and out.

Thanks Rod, Put regular fuse in yesterday and turned lights on for about 20 minutes and there was no flickering so I hope this solved the problem. Greg