I am looking to replace my trim tab switch with the digital illuminated switch. My current switch does not have the lights that go up and down with the trim tabs. Is this just a simple switch replacement from my old switch to the new one or will there be wiring harnesses to replace as well?

It depends. Some of them have a separate controller and some don't. Either way, it will be plug and play, all Duetch Connectors. So, if you don't have the separate controller, you unplug the switch and plug in the new one, there will be three plugs. If it does have the separate controller, you remove your old switch, connect the controller to the power plug and left and right actuators, and then connect the switch to the controller with the remaining plug. My last two boats had the separate controller, and I installed the whole tab kit on both of them. It is super easy to do, I bet it takes you all of 15 minutes to complete.

Thanks