I have a 2002 TL Type-S with OEM Bose 6-disc changer head unit. When the sound system is powered on, it doesn't turn on right away. It just stays off, and the red "security" LED intermittently blinks. After a while, the sound system will spontaneously start working and abruptly stop again after a few seconds with the security LED blinking.

It seems like it couldn't be a loose power connection to the head unit since the security LED is still blinking when the sound system won't turn on. I'm also thinking that it can't be a blown fuse since the sound system wouldn't work even intermittently if that were the case.

Many years ago, I installed one of those RCA aux input adapters that plug into the FM antenna port on the back of the head unit. It's possible that this adapter is starting to malfunction. The question is: is the behavior of the sound system/security LED consistent with what would seem like to the head unit that of the antenna being disconnected?

I want to be certain since I don't want to replace this adapter only to discover that it's the head unit that is malfunctioning. Thanks in advance!

 

I just realized that it's not FM antenna adapter. It's an adapter for the CD changer port. In order to use the aux port, the head unit shows CD-99.