Passenger Break light and turn signal doesn't work with lights on.

My 1986 Ford F150 Lariat was used by the previous owner to pull campers. So one of the first things I did was get I underneaths​q the back end to see the damage that was more than likely done when the trailer plug harness was installed. And what I found was that he spliced the trailer light plug into the trucks Factory tail light wires with indoor wire nuts. Realizing how ridiculous this was, I proceeded to remove the trailer light wires attempting to return the tail light wiring of my truck to its original state. I thought I had accomplished this until it was driving at night for the first time. That's when I turned on my lights with the light toggle switch on my Dash and realized that once turned on the passenger side brake light and passenger side turn signal would not work. When I turn the lights off, both the brake light and turn signal would work again. Can any of you knowledgeable folks give me a clue as to what is going on? Also I have spent countless hours, no exaggeration, trying to find a decent wiring diagram for the tail light/tail lamp harness for this year make and model of truck online with nothing but false leads and useless blurry uploads. Can anyone please direct me to a website that actually has A: an actual diagram for this truck. And B: a list of which colored wire performs which function. Also if anyone knows of a decent just kind of parts website for older trucks especially for Ford F-150's, I would love to know about it. I would be forever in your debt if you could please help me out with this. The last thing I need to do is be pulled over on my way to work or smashed into because of a problem that I could have fixed. Thanks in advance for all your help and for taking the time out of your day to help make a stranger's life feel little bit better.