I had same problem and after Jeep dealer wanted £1,600 for replacement (he said not repairable)
After weeks of trawling the net, I found a repair shop in the US who had a contact in UK and they repair the Chrysler radios (Mine is actually built by Alpine for Jeep GC unit) These guys knew EXACTLY what the problem was.
Their name is - Factory Car Stereo Repair Inc at http://www.carstereohelp.com/]
They put me in touch with a UK repair shop that appear to know what I am talking about for a Jeep repair. The UK shop is Maple Audio at Maple Audio
Got my sat nav fixed for £280 + Tax (approx $400) Good as new now