Bringing up this ancient forum… I’m having the same exact issue as Troubador and this the only forum I’ve found with the same issue! The headlight switch connector melted a few weeks ago, I replaced it and the headlight switch. Everything works perfect when the headlights and taillights are on (3rd slot on the switch) but with just running lights (second slot) the park/tail fuse blows. If I pull the switch to the 3rd slot then put the fuse in I can drive fine with taillights and running lights, it only blows if the switch falls into the 2nd slot. Troubador, did getting a part from a junkyard fix your issue? I’ve tried 2 switches from Oreilley and 1 from autozone and they all act the same. Any ideas? I have an 87 wagoneer XJ