Hydraulic Trunk Problem

My 92 RS has had issues with the wipers not always working. If I wiggled the white wire they would usually come on but as soon as I used my signal they stopped. So for the better part of 3 yrs I've driven without working wipers. Until a few weeks ago when my boyfriend of 7 yrs who happens to be a mechanic (so I hear) decides to hook up a switch and splice into the wire to the wipers & to the battery. Something like that, anyway it worked for a day or two until frying the wire. My problem is I opened the trunk using the release button it opened fine but will not latch, no light comes on either. Where do I begin to look for the problem? I assume its a short although I checked fuses with no luck. Sorry for my lack of knowledge. Need help

Start by checking for power back at the hatch motor (I assume you have the electric pull down). If no power to it, you'll need a wiring diagram to trace the wire to its next stop going forward.
If there is power back there, you have a relay and switch that operate the pull down.

if the lid releases then there is power to the pull down as they share a common circuit. my bet is the wiper-trunk latch problem is unrelated....the pull down on my 91 formula stopped working.. turned out was just a bad prong on the harness. undo the harnesss at the pull down motor and check it out. if its fine its likely the relay on the motor