Stackerman, You didn't mention what model truck you have. I have a D350 with all of those running lights and clearance lights on the fenders. When I pulled my trailer it had clearance lights also and my switch burned out. I put a relay on my trailer so that the light switch only turns on the relay and the power from the trailer batteries runs the clearance lights on the trailer.
Walt
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91 D350,New style BD Brake,Gear Vendors O/U Drive,Gauges-Pyro,boost,tach,trans,rearend,brake,
Airbag rear,Transfer flow tool/tank, Exh. sys,Rino lined bed, Alcoa Mags,SS runningboards.
16cm.