Side Marker Lights issue
 

1985 Chevy G10 Van, so I installed LED lights., and ever since Ive been having issues like, my front turn signals were extremely bright in park mode and would flash dim when turn signal flasher was on.., ok so I reversed the bulb in the socket and polarity and now the front turn signals are at normal brightness when in park mode and brighter when signal lights are activated! GREAT! everything in the rear end works as it should, rear side markers are bright, tail lights work good etc! my issue im having is my front side marker lights are not working properly., so when my headlights are off., I have no signals on my front side marker lights or park indicators., as soon as I turn the headlights on to either park mode or headlight mode the side marker lights turn on and flash when turn signals are activated., except in park mode they are really dim., they flash bright when turn signals are on but in park mode they are really dim., much more dim than the rear side markers.,., so again., when I turn the parking lights on., my front side marker lights are really dim but signals flash at a normal brightness,.,., when I turn off the headlights the front side marker lights are completely off with no signal flashing....until I turn on the headlights. I hope I didnt repeat myself too much and that I'm making sense with this issue I'm having., any ideas or further questions anyone needs to better figure this problem out.,.,. before I installed the LED's I had them working beautifully, but then one day my front side markers went dim so thats why I decided to go LED to see if that would solve the problem but its doing the same thing with the LED's

I suppose I could put the original lights in and see how they act because I know the LED's can be a little finicky

ok. I have an update! I’ve been working on it for a couple hours and I have determined that my problem lies in the side marker wiring.? Possibly? So Basically, if I remove the bulb, whether I use LED or incandescent, from the marker lights everything works perfectly as it should. As soon as I plug in a bulb into the side marker lights, all hell breaks loose. First of all, as soon as I plug a bulb into the side marker the corresponding front parking light will brighten up. This happens the same to both sides. Then all of what I mentioned in this post takes place. I’m totally thinking of re-routing the wires front the side marker socket directly to the front turn signal and parking wires, so that the side marker lights mimicking the front marker lights. Does that make sense!?

Sounds like you have a bad ground somewhere in the circuit