2003 379 led headlight issue

Awesome thx for the help

 

I had the same problem in ND oil field with mine.
Hired an electrition to trouble shoot the issue and turned out to be the R rest taillite was rotted out.
might check that out.also your relay switch down on left foot panel.
Not sure with one though .
I replaced it and they started working . Both lights on right side were on and I would switch to high beam and would switch to out her side. Replace relay not fuse,and check for corrosion at R tail lite

 

Make sure that the wires coming from the truck headlight wiring harness is the same color as the ones on the new LED headlights. You might have to switch the pins on the plugs so the green plugs into green, black to black and red to red. Otherwise they will not work correctly or at all in some cases. You can buy a conversion kit on Ebay H4/9003/HB2 Headlight Socket Converter H4652 H4656 H4666 H6545 Adapter Plug | eBay