Instruction: Given a question and the related document, and generate the answer to the question based on the information provided in the document.

Input:
Question: Does the Tunelink drain your car battery?  Do you leave it plugged in all the time?
Document: I plugged this into the cable Cadillac provided and now I have one connection and the phone is not under the armrest. This was a problem for me because I keep forgetting to take my phone when I leave the car. This turns out to be the best solution for me.If it wasn't for the loss of functionality I would have kept this unit. The sound was great.
When I first received my TuneLink, I plugged it into my SUV's cigarette lighter port and my iPhone recognized immediately and started playing music... for 3 seconds.I unplugged it and then plugged it back, but this time the TuneLink was no longer discoverable.
Download the app, and in the settings you can fix this issue. To the negatives I would add the bluetooth drain on the battery. We all know this is just a part of using bluetooth; however, I find my phone's battery in the red zone at the end of the day much more than I use to.
I'm one of those that rarely leave feedback. I will state, I bought one, plugged it in,  paired it within about 30 seconds, and it worked great! for about 30 minutes. Then,  it quit. Dead. No lights, nothing. So, I used Amazons return program. Had them send me another one. Plugged it in, paired it,  worked great! for about 2 hours. Then, quit. Still had a light,  wouldn't pair.
After a few tweaks, it finally worked, and the audio really was amazing! Unfortunately, it would disconnect sporadically, and reconnect unexpectedly. Sometimes, we would leave the car and it would reconnect automatically when we got back, but most of the time, IT DID NOT CONNECT AT ALL. Very disappointing.It was very frustrating to use because pairing was inconsistent and not worth the grief. I had to send it back. Three stars for the audio though.
This works perfectly! Trying to get sound from the tuner didn't work well for me. The sound was choppy and unclear. I still have a tape player in my car, so I plugged the tape player cord into the Tunelink, and play my songs through the Bluetooth feature on my iPhone. Sounds good! This product is life changing. I love it!! !
I turned off the FM transmitter feature with the TuneLink app...so I cannot comment on it's sound quality.My car suffers from a bit of engine noise when power is plugged in, and with my Griffin unit, I had to use a ground loop isolator to remove the engine noise. I was hoping that the "Humbuster" technology would let me eliminate the need for the ground loop isolator, but no luck.
I always put my iPhone 4S in a dash holder in my vehicles and hook it to the TuneLink charging port because I like the phone accessible, I like to keep the phone battery topped off, and related to that, I frequently use GPS navigation which draws more heavily on the phone battery than most other Apps.
I ordered this product a little over a year ago. It worked fairly well for about six months, although the autoconnect and sharing between multiple phones never worked exactly as advertised (it only auto-connected when connecting to the same phone; when switching phones it had to be re-paired manually every time. Changing the sharing settings had no effect.) After a while, though, it started to drop the audio (but the bluetooth stayed connected), and had to be unplugged and plugged back in.
It plays the audio just fine. The issue is when I power cycle. Tunelink has a really cool function were when it powers up it opens the last audio program you were using and starts playing where you left off, even Pandora and other apps. But it doesn't do that for the Samsung video player. Infact if I leave that video player going when I power off the Tunelink, it totally fails to connect when I power it back on.
Answer: it does not drain my battery and it is left in maybe 50% of the time