do not cut the radio harnesses! The connections on the lincolns get more complex

Take a test light 12volt probe or meter & then ground the probe then check the orange , yellow & red wire usually red is what we call a constant & life all the time, then once u know the constant turn on the ignition to just Aux & either the orange or red will now also be hot too or live, then try the key in the run position & see if both those wires now r live & once key is out only the one is hot.Most of the time they use a blue wire for the antenna but they could be using even a yellow.That is simple to test bec once you've the stereo connected up to power & speakers , turn it on & have the wire u suspect is the antenna wire connected to the right wire on the stereo.As soon as the stereo is turned on the antenna should be going up & if it does not then check if the wire on the radio for antenna has 12volts once the stereo is turned on.

Hope that helps & best of luck.Yes wiring can be headaches l know first hand bec I've installed many stereos & that is one reason they sell adaptor harness kit is for new stereo installations.But even l do not pay extra money for harness is l just take the time & wire it in myself on my cars.

for premium sound system. hot all the time w/p ,hot in run& acc.w/lb,light lb/r,ant.o/y, ground bk

12 v at all times = w/p
ground = bk
antenna = o/y
12 v in acc and run = w/lb
good luck

Hi, this is audio circuit diagram for 91 towncar, version with amplifier in the trunk. Maybe you find it useful:
http://img187.imageshack.us/img187/8572/91fordsoundsystemsyr9.jpg