Clarion stereo system (cassette) issue

[340DA]

I have an issue with my Clarion model M5470 stereo system. It's original equipment with my 2000 340 Sundancer.

FYI: The radio plays both stereo channels just fine.

I purchased a bluetooth adapter that fits cassette player slot so that I can connect my iphone and play my music rather than just listen to the radio. It has worked fine for several years. Beginning this year, only 1 channel is playing, the right channel. The left channel does not play anything at all. This only happens when using this cassette adapter.
I suspect that the issue is with the cassette player itself because I have 2 of these adapters. One is bluetooth and the 2nd is hard wired. This issue occurs when using either of the adapters

Any thoughts what the issue could be? And how to resolve it?

 

[Golfman25]

What's a cassette player?

Time to uprgrade the radio or just use a wireless speaker.

 

[Parker Brooks]

I threw a new Bluetooth stereo to replace the clarion. Works great! Here is the description. Easy install. Works with apple.
Sony DSX-M5511BT
Marine audio package: Includes DSX-M55BT digital media receiver (does not play CDs) and two 6-1/2" speakers