Congo (on page 20) put in info about changing the "conditioning" and the hissing sound being due to max output to the speakers...And an "amp" toggle, and fixed his...this may be the fix for the hissing everyone is getting? I'm going to pull the trigger on the CC3 and try to install this into my '04 LC100. The teyes.com site has FAQ area that trouble shoots a bunch, and this thread has a ton of help too, so feeling pretty confident.
What I did:
Getting factory volume knob to work: there are 3 "female" connectors that I did not connect back to the factory bottom "tape player." Connected them and the factory volume knob is working.
Hissing fix: I messed with the Sound settings and the Power Conditioning settings. By default, it is set to max which is causing the unit to send full power to the speakers all the time. Adjust the Power Condition down to 30 (halfway) - 45 and it helped rid the distortion. There is an "Amp" toggle, turn it on.