89 lincoln town car factory amp?

I have a 1999 lincoln town car , and mine has a factory amp,  its in the trunk rt side.i try to install a new one but cant fegure where to tap for my input , what is the best ,i tried the rear speaker it didnt work, if you know something pls, let me know, thanx.

try using a batery with two leeds coming of it,one on the + side and one ont the -ve side. probe the wires on the 10pin plug see if you can get anything to pop. if you cant it is amplified .

blow what up forbidden? what in an 89 town car are you going blow up probing wires at  the back of the deck with a 1.5v battery?

For an untrained installer I am not recommending probing wires with a battery, the untrained may not just tap into a speaker harness with 1.5volts, but may tap into something that is not supposed to have voltage in it at all, and what if they were led to believe that this was an assumed practice to test all leads in this matter, this is why I don't recommend testing leads in this fashion. I have seen people testing leads with 14.4volt Makita batteries! Maybe I should have been a little clearer with my reply, maybe you should have specified a 1.5 volt battery, no offence intended. Now even though this post may have come from a dealer, any person who reads these posts, and alot of people with limited knowledge do, all these people can draw conclusions, we need to be sure to address this fact. For you or bberman or whoever knows what they are doing, well that is a different story. Even a dealer can have a new installer and that installer is going to have questions.