1989 tail lights

Okay, so my tail lights will work, just not while my headlights are on. If I put the parking lights on and pull just a touch more, then the rear lamps will go on. So I can eliminate a fuse or bulb problem seeing as I've already changed the fuse. So the only thing I can think of would be a faulty pull switch. I can't afford to get it fixed. And ideas on a quick fix?

(One idea was for me to reroute the wire(s) from the switch to something like my heater switch. I know it could work but I don't even know which wire would be it. Does it even run behind the radio?)

Help would be greatly appreciated. Thank you.

Zip on the quick fix but, I'd be shocked if a junkyard charged you more than $10 for the switch. Check around.

Good, but I don't even know how to go about replacing a switch. I've nevcer done it before. It's a knob pull switch.

This might help: http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/10/cb/f3/0900823d8010cbf3.jsp