Hi Folks,
'96 Ram diesel, hooked up trailer (for the first time since owning truck) to check lights etc., turned light switch off when finished. Next day noticed very dim lights, batteries run right down. I guess the extra lights put a load on something...spare (also used) light switch swap doesn't change anything, lights stay on even with switch unplugged. Pigtail to switch has been spliced in at some point, no sign of any melting there. Any suggestions on where to look next?
Thanks,
Seann

 

Sounds like battery power wire is rubbing onto your headlight wire at the output of your switch

 

Or a ground is back feeding to find a ground source for something through the headlights ....

begin by installing headlight switch and start systemically pulling one fuse at a time till the go out .... Then trace that part of harness

 

On my half ton conversion I had dim tails staying on could not figure it out then I read a post where a guy was having a similar issue and it was the bulb in the 3rd brake light and I thought it sounded fishy but I had nothing yo lose so I checked it out. What I found when I pulled it was the lovely little mice that we all love so dearly chewed the coating off all the wires to my 3rd brake light. So I went down in the cab colors coded them and cut all the wires going there and when I have time I'll make the repair. Just a thought and something to look at.