ALTEREGO

I know is going to be hard for you guys to help me remotely through the forum, I can tell because just thinking about how to describe the issue feels complicated, but lest give it a try.

My T100 2WD Base 2.7 Engine Auto Transmission has a switch (see pictures) to manually turn the back lights and dashboard lights on/off (I bought it like this). While inspecting all the truck's lights I noticed that the front parking lights (corner/marker lights?) were not turning on at all. I removed one of the bulbs and upon inspection I wasn't 100% sure the bulb was bad. I decided to buy LED replacements anyways and after installing the new LED lights they still did not turn on. After some more research I found out that the corresponding 15A (if I remember correctly) fuse located in the fuse box under the dashboard (driver's side) was missing. I installed a new fuse and the new LED parking lights are now shining brightly.
Sadly now if I have the headlights on and I turn the switch for the backlights/dashboard lights on, the dashboard light does not turn on. If I turn the manual switch for the back/dashboard lights on first, the dashboard lights do turn on but if I turn the headlights on the dashboard lights turn off. My guess is that the previous owner realized that by taking out the fuse for the parking lights (not sure what else that fuse controls) the dashboard light problem was resolved. That might be the easiest solution since the parking lights are not as important as the dashboard lights in my opinion.
I know nothing about electrical issues, wiring, etc. but is it plausible that somehow the current wiring set up is drawing too much power leaving the dashboard lights out of the necessary voltage to turn on? Is it possible that installing new LED lights that required less power the problem can be solved? Please advise, thank you!


This is the manual switch to turn dashboard and back lights on and off

With the switch on