Truck is a 1995 F350 CCLB, 460, E4OD, 4x4 (probably over specific for this issue, but better safe than sorry)

I'm no stranger to automotive electronics, been working with them for 5+ years now, but never encountered an issue like this before. Basically the entire truck has been converted over to LED lighting, excluding the Over-head Cab Dome Lights and 3rd Brake Light.

I know with LEDs you have to either put resistors in-line for your lights, or use an LED Flasher unit in order to prevent the hyper-flash issue. I chose the latter technique, so that my wiring stays intact, but for some reason, when I mess with the system at all, I get these same results EVERY. SINGLE. TIME.

With the entire electronic system assembled, everything works as it should. However, if for any reason I partially disassemble the system (take out a taillight to inspect wiring, fiddle with trailer connector, etc) and later test the system as I'm finishing reassembly, the turn signals won't flash like they should, neither up front or in the rear. They just seem to come on a little bit, like they're not getting enough power to fully light up, or even to make the LED flasher unit *click* like it's supposed to when you turn. Here's the kicker though...When I finally get so confused/frustrated that I just put it back together and leave it to figure out later, somehow the system works PERFEFTLY when I test it???

Does anyone know what's going on, or what could cause this issue?

 

To PREFACE this: before I purchased the truck from my Dad, the only issue it ever had regarding lights was that the driver's side brake light would intermittently stop working. No brake lights, no turn signals, nothing.

By swapping the bulb out, and it working perfectly in the passenger side, I looked further up the line and was able to diagnose the issue as being an oxidation build up on the copper plates inside the turn signal switch unit. After removing the oxidation and basically remanufacturing the whole switch, I reinstalled it and had no issues whatsoever.

That is, until I decided to convert to LED bulbs. I have had both the bulbs and the LED Flasher unit replaced, but the issue persists when I mess with the system.

Why does it do this? What's the most likely cause? Seems everyone I talk to says there's just a short somewhere in the system that's causing this issue, but they don't have any experience with LED stuff either...

I just don't know enough about LEDs myself OR the way these trucks' electronics systems work in order to track down a bug any further?