89 TC Radio question

[tjackmil]

I have an 89 Tc which I have owned for 5 years. During that time, the rear speakers have not worked. If I position the joystick to full rear and crank up the volume to full, I get extremely distorted sound from them. At the recent Chrysler Nationals, I spoke with other TC owners who suggested that I might have a problem with a ground connection. This past weekend, I pulled the right lower speaker out and investigated. There were several wires from the harness connection going into an electronic module (amplifier?), with two wires coming from the module and soldered to two connections to the speaker. When I grounded one of those connections, the entire rear speaker system came to life and sounded great. However, when riding that evening, I detected a burning smell which I feared might be caused by my grounding jumper, so I turned off the radio and headed home to investigate. Upon pulling the speaked out again, I determined that the odor was coming from the speaker, and that the electronics module was very hot. However, my ground jumper did not show any signs of overheating. After all of the above discourse, my questions are: 1) could the grounding jumper present a fire hazard?; 2) Given that amplifiers typically operate quite hot, was the burning odor detected caused by years of accumulated dust "burning off" of the electronic parts? I would really like to reconnect the grounding jumper as the sound quality was greatly improved, but I am not prepared to risk a fire. Any thought on this issue would be appreciated.