Mr. Eclectic

Bought a tape adaptor along with a wireless Bluetooth transmitter to bypass the factory HFL, which was of course fried (and a poor design to start). It worked sufficiently for a few weeks, then stopped. Tape is not accessible, i.e. when pressing the "cd/tape" button, only the CD player will illuminate and function. Shortly thereafter I developed a battery drain, which I traced to the same circuit with the radio, HVAC, dash lights, mirrors, etc (I'm fairly certain).

My question is simple: Ciuld the inoperable tape player be the cause of my battery drain? If so, what is my best option for fix/replacement? New (used) factory unit? "Upgrade" to factory navi? Line level booster to aftermarket amp(s) and new h/u and separates plus sub(s)?