Will this work with my truck's existing wiring?

Yes. This is a direct replacement for the factory cab light, so it connects to the same electrical points without modification or splicing.

Do I need to do any prep work before installing?

Remove the old light fixture and clean the mounting area. The black housing doesn't require painting—install straight out of the box.

What if the LED fails down the road?

The bulb is user-replaceable. Standard LED cab light bulbs are inexpensive and widely available if you ever need a swap.