Wiring problem query

Is it only rear tail lights and side maker lights causing the issues?
Rusty contacts leds to the positive end the earth been bridge and fuse blowing
Open each lamp, disconnect the positive wire ( contact touching the tip at the base of bulb) at one at a time and check if the fuse is still blowing.
start by disconnecting the top marker lights first because they prone to branchs hitting them and water gets in destroying the contacts.
Next do the same on the lower side marking lights on the side next to the ditch because that where the most of puddles are.
Keep going until the fuse stops blowing then the last disconnected lamp is the problem.
If you have a trailer socket disconnect it first, they are very problematic