maybe in 2024 someone else is puzzled by the search for the loss of AM signal reception. I am a perfectionist in relation to electronics and most likely got to the bottom of the truth - the reason for the lack of reception in the AM range. I studied the forums of Jaguar, Volvo, amateur radio communications and came to the conclusion that the piezoelectric filter in the tuner module is to blame. Inside the filter there are traces of copper oxide - green, they also write that there were many problems with the communication equipment in which these filters are used. The filter is from TOKO, PROBLEM FILTERS WERE FOUND IN THE EQUIPMENT OF 2007-2010. I WILL TRY TO INSERT A PHOTO.
I moved the tuner module from the donor but it still doesn't work, then I unsoldered the protective screen and found that the piezo filter was covered in a white coating, there were no traces of moisture around, obviously this is some kind of material that oxidizes the filter contacts

http://www.cqham.ru/forum/showthread.php?36061-Фильтры-LTM450 (link to problem with filters in communication equipment)
https://www.volvoforums.org.uk/showthread.php?t=272793(volvo forum)