Volume goes down on its own, also changes stations on its own.

Yes, buy a remote control :>) They are readily available, no need to program and can be obtained from Amazon, eBay and specialty remote retailers like www.remotes.com

Google

Seiki (model) replacement remote

https://www.google.com/search?q=seiki+tv+replacement+remote

The most likely reason for your issue is a dirty button and the contacts. Switch Contact Cleaner may fix it.
..

2008 NISSAN ALTIMA SERVICE REPAIR MANUAL DOWNLOAD

they have the best manuals :))

https://chrome.google.com/webstore/detail/browse-manuals/hogjdcdnnjbjbbicpgmhkhkiemhbacml

Did you find the problem with your radio Terry? I have a 2005 X type and the radio has just suddenly started doing exactly the same thing - cant change radio station or use steering controls, only the volume knob works.

You need a new clockspring as the windings are become frayed internally.

I wonder if your problem with loud volume occurs primarily on commercial breaks, when you turn down
the sound and then, since the sound, for the program itself, is so low in volume, you have to turn it way
up again to enjoy the program?

If this is the case, and there are no other problems with the set, this may not be the set's problem, but the
fact that commercial material is broadcast at a higher volume than program material by some outlets, so
that while you are in the kitchen, during commercials, the sound of the commercial can still be heard.

just like any computer, unplugging it for 30 seconds or so may cause it to revert to initial settings.... if you take the battery terminal off you will reset everything and that is not necessary.... find the fuse for the radio and yank it.... see if it helps. IF NOT, probably a burned programming mode... hope you like that station....

have you try having the steering wheel controls replaced? if so the problem is in the radio

Reset method is power + volume + at the same time

Probably, however, you just need to go to the new station and press the play button to confirm the radio station change - then it will play the correct station

Unplug AC electrical cord for a bit then plug in and see if it resets.......................T.