2012 Radio not storing preset stations or returning to last station listened to

[Jhgrn3]

In my decade long experience with my 2011, I'd get electrical gremlins throughout this entire vehicle with a weak starting battery/alternator. I've noticed that my HD radio cuts out whenever my alternator fails...I have no idea what that correlation would be. The first time I noticed the stations playing without HD my alternator crapped out on me. I bought a used one off of eBay and after a few months the HD radio cut out again and the following week the second alternator failed. The third time with the brand new dense alt, I developed a valve cover leak which leaked oil onto the alternator and prematurely fried that one as well. This time along with the HD radio missing, my clock and date/time would reset each time I used the LR4. Also had issues with the key fob not working and the rear hatch working intermittently due to the power issues. Once it has a fresh battery and working alternator all was well. I'm not saying it's your alternator, but make sure your starting battery has at least 12.3 volts after shutting the vehicle off for a few hours and make sure you have over 13.2 volts when running. I have anywhere between 12.3-11.9 volts after a few hours of sitting (I need a new battery as 11.9 is too low, but everything works for now), and I get 13.2-14.5 when running. The alternator constantly changes its charging profile so it's not a traditional system where you'd say anything under 14 volts is abnormal. anything above 13.2 volts is "charging"

 

[Jhgrn3]

Before you go crazy, there may be a simple explanation. The power supply for radio function and radio memory are separate. It may be something as simple as a blown fuse for the memory. I would look there first.

In my 2012 LR4 you can press and hold the preset radio buttons to store the station that you're currently listening to and this works fine. As soon as you turn off the car these preset stations return to 88.3. In addition; when you start the car the last station that you were listening to (say 107.1) is always reset to 105.3.
If I use any other input (like the CD player) then the system recalls where it was before turning off the engine. This seems like a battery issue just on the radio portion of the entertainment system... I'm curious if anyone knows if there's a dedicated battery or has other ideas how I might fix this? Thank you.

 

[Longtrail]

Thank you, this is highly relevant then... Do you happen to know which fuse it would be? I'm assuming the ones inside the glove box? Do you happen to know if the radio function is in the touch display or the CD player portion of the entertainment system? I'm curious in case I want to swap out the radio (having checked the fuse!).

 

[Longtrail]

I tested a bunch of fuses in the fuse area directly behind the glove box, I think fuse 1 and fuses 64 through 69. One certainly caused the radio system to power off/show as unavailable. The fuses were all OK in terms of continuity. I think my next step is to pull out the display unit and CD player and look for disconnected cables; I read on a few websites that there is often a yellow cable that is +12V with the ignition turned off (it's sometimes red as well); I'm going to see if I can find something similar...

 

[greiswig]

This is a total shot in the dark, but...many electronics have an internal battery to store certain info, usually a little 2032 coin battery or something. Is it possible that these have that as well?

 

[Longtrail]

I'm on the same page, here's what I wrote in my original post:

I'm curious if anyone knows if there's a dedicated battery or has other ideas how I might fix this? Thank you.

If I knew the answer to this then I'd be straight in there but I don't want to rip it all apart until I know a little more... It would be great if anyone knows???

 

[Longtrail]

I like to follow-up on issues when resolved! In this case I managed to get wiring diagrams and finally decipher those diagrams. The Audio head unit is stored behind the heater controls; it contains not only the CD/DVD player but also audio functions. This head unit is supplied with a constant 12V (battery voltage) even when the vehicle is not running. This voltage can be measured at pin 1 (purple color) of the light gray connector that goes into the back of the audio head unit:

You can either ground on the vehicle or use pin 8 (black cable). Needless to say I have about 12.4V which then points to an issue with the head unit itself. The unit was not in the best of shape, it looks like something has been spilled over it (Eugh):

I never knew this when I originally posted! Anyway, I purchased a replacement unit on Ebay and now radio presets and last station are recalled (even when power are not provided - so it either has a battery or some sort of solid state memory)! I hope this helps if somebody comes across a similar situation. To reach the head unit the following video from powerfulukltd was invaluable (Thanks to them):

And diagnostic skills from this one (Thanks to Ivan):

 

[ryanjl]

Looks like someone spilled a soda on your dash at some point? Anyway, thanks for the follow up.

 

[Longtrail]

Thanks for your help Ryan, yeah - big cleanup one evening, it wasn't limited to just the radio!...

 

[ftillier]

Will you crack open the old unit and see if there's a battery inside?