Why does my Right side Lighting not work?

[xxx-Lost-Soul-xxx]

So after a long issue putting a new Alpine deck in the car, I got it to work,and it sounds good,everything was good. Till you turn the car over.
The #23 Fuse keeps blowing,and the right side of the car will not light up,The License plate lights & right tail light Have continuity.Everytime i put a new 7.5 fuse in there It pops,so im thinking its as short to ground.

I followed the Guy on e30 tech to install a alpine deck,and it does work,till you turn the lights on,so i cant drive this at night.
Headlights work,But the right Tail does not,along with the cluster lights.

I took all the side marker lights out to see maybe thats what it is. All 4 lights have had water in them at sometime,and 2 of the 4 bulbs were cracked,along with there connectors pretty nasty looking. Any chance this is it? I ordered 4 new Marker lights today from worldpac,because i need them anyway.

Thanks

[DaveSmed]

The side marker lights suck, fill up with water, and rust the legs off of the bulbs, but thats just one of the many habits of these fine automobiles. Stick with what you did last before you had this problem, namely the headunit.

Pull it out and recheck your wiring, the illumination wire is almost certainly causing the problem.