My 2003 LS430 of course does not have a stock AUX jack, so I have to use a cassette adapter.
The problem is that no sound comes through the speakers even though the navigation display says "play". Ive tried multiple adapters and neither have produced sound. Actual cassette tapes work, so I know the cassette deck does work. Please help. I'm getting tired of whats on the radio.

 

What kind of device are you plugging into it? This may sound like a dumb thing but, when I first plugged my phone into my cassette adapter, nothing played and I couldn't figure out why, it was because my Android phone has two different stored audio volume levels, one for speakers, and one for the line-out. So even though volume was on full before I plugged in the audio jack, once I plugged it in, it went back down to zero. Took me a few minutes before I realized what was going on, but once I turned the volume up again it worked fine.

Other than that, not sure where to point you. My cheapo wal-mart cassette adapter has been working ok. I hope you figure it out!

 

^ What he said! Especially if you say a regular cassette works and you've swapped different cassette adapters, it leaves the source at fault.

I know my android phone has 3 volume settings:

Top is the ringer, mid is for media sound, and 3rd is for alarms. Look in to that, whatever phone you're using.