I'd put it off.

The most likely way it would be LESS than $200 is if someone comes out, checks the wiring between the junction box, and tells you, "We can't fix that without digging up your deck!", and gives you a bill for a $100 service call. It's also possible that there is an easy to fix wiring fault elsewhere. But it's somewhat more likely that, if that's the case, you already got some substandard wiring which ALSO may be expensive to fix.

When I've repaired lights, it's rarely been easy or cheap.