Light issues 2016 VNL 670

1. Trailer marker lights not working...tested on 5 different trailers...2 lit up 3 did not (1 did at first then went out). Checked voltages etc and because it was time anyway replaced the pony tail. Still no marker lights. A smart older guy told me to start with the courtesy light (you know the switch we flick on and off to thank other drivers for letting us in). I already checked fuse (someone had put a 30 where it should be a 20..fuse was fine but I put a 20 in anyway). Anyone ever replaced this? truck is currently in shop for new shocks but I literally have very little confidence in their electric abilities (side note last week the turn signal indicator broke off..i bought a new one and replaced it myself. ...marker light issues same before and after...and marker lights on the truck work). or has anyone had similar happen??
2. Headlights..we replaced halogen lights with LED about 6 mths ago. Last week while driving in the dark my headlights went out. Flashed the high beams they came back on. Luckily the next stop was a Loves and they replaced the LED lights with the older style..saying the wires in the LED lights had kinked. I did not drive in the dark again. When taking truck for shock service I turned on lights..(pre trip they worked). Got message Headlight left low beam short circuit. My husband was in front of me in a van and told me the light was in fact off. So I turned the lights off and while enroute to the shop my husband said the left headlight was flashing on and off irregularly. Would you suggest I replace the headlight switch to start? that is my idea any way.. Not "mechanically" inclined but not afraid to watch a video and do this stuff it is not hard if you follow directions .

 

Yes I replaced the ponytail though the voltage said it was fine but it made no difference. I will try the disconnect tomorrow when I pull it out of the shop. I don’t believe they are related I’ve had issues with the headlights since I bought the truck three years ago but I’ve never had the lights go out on me lol thanks for the reply and suggestion!

 

Thank you for the suggestions! I am picking truck up tomorrow done or not from the place that has had it since Thursday a.m. to change the shocks and fix the lighting issues. I am no expert far far from it but there are lots of youtube videos and guys like you who have had way more experience than me....i am not afraid to try and fix it myself it at all possible. I wlyk what happens.

 

so thanks to those who responded. We ended up by passing the harness and direct connecting the lights it worked!