Probably something I did to my 08 MCS, HD, but maybe not.
When I put my key in, the radio comes on if it was on when I shut the car off. When you push the start button, the power to the radio is interrupted until the car starts, and when it does, the radio then comes up in AUX mode and you have to switch back to Tuner for radio. I've tried turning the radio off and on, off when I kill the car and pull the key and any combination I can come up with but the scenario is still the same. Minor annoyance but I'd like it to default to radio and stay there. Any thoughts?

Relatively new to the car, but not long ago the radio acted like the reception was getting bad on all stations. Found you could thump the steering wheel or side-load the on-off button and it would clear some. I figured a switch or something simple was shorting. Took it to the dealer and on extended warranty (thankfully) they replaced what they called the receiver. OK! $2200.00!!!

The OEM Head Unit (receiver) does more than just be a radio. it handles many other things like all the dash idiot lights and warning noises etc. That is why it is so expensive.

Now this is also really a computer unit and as such the programming can be corrupted.

The easiest thing to try that clears many of these type of strange activities by the radio and other computers in the car is to disconnect the battery for a minimum of 30 minutes. Some people will tell you to press the brake pedal after disconnecting the battery but that only assists in clearing the 'footwell' module which controls the exterior lighting it does nothing for the head unit.

So disconnect the battery for a minimum of 30 minutes and then reconnect it and see if that clears the problem.

Thanks for the info. I finally had the opportunity to disconnect the battery and after about 40 minutes, the first trial was successful! It held the tuner setting during the start. Is 30 minutes the magic number for dumping memory? Anyhow, it worked and I thank you.

I would not necessarily say that 30 minutes is the 'magic' number but it has to be left long enough for all the circuits to drain. Some have reported less than 10 minutes and others have not been so lucky so if it is left 30 minutes it would work most of the time. There are a few instances where this does not work but at that point the car then needs to be reprogrammed.

Update: The battery disconnect only worked once then it went back to it's old ways. However I have found the problem. It was the battery! I left stuff on for about 15 minutes and when I came back to it the battery was dead as a door nail. Got a jump, drove around. Next day, 1st start barely cranked it, but it started. Ran around without shutting it off for a while, hit the grocery and came out and it was dead. Next stop Sunday night was AutoZone for a new battery - $160! (I guess they are all made in about the same factory.)
Now, when I start the car, the radio doesn't even turn off while the car is cranking\starting as it did before. It even seems to run better. Lesson learned that if the car is doing strange electrical things without any other apparent reaso, check the battery health.

Yes a bad battery does cause all kinds of crazy things to happen with the electronics in the car and it always seems to be different with different cars.

Hi Mike

I'm having the same issue with my tuner setting reverting to aux. Did you find your battery replacement to be a long term fix for this issue?

Thanks for any info.

Yes! I have had no radio issues what so ever since replacing the battery. I acts like I'd expect it to. It was about 2-3 weeks that the radio wasn't working right until the battery gave up the ghost. Just prior to that I had some $2200 radio part (receiver?) replaced on warranty and I had an appointment to take it in on the Monday following the Sunday that it finally gave up. I cancelled the appointment for a re-check and have been good to go since. July I think?

Thanks for the reply. My battery is pretty weak so that's probably my issue also.

Thanks again!