Good afternoon or appropriate period of time where you're at,
I have a pair of K845BT headphones, they work off 3.5mm jack, since I'm not very smart i removed and tested the speaker too, but that's beside the point.
I've traced it back a little bit, now i know what some bits and pieces look, but I'm no expert. Checked the fuses, visually most of the board looks good too, however the Bluetooth strap-on board has a surface mount component that is chipped, probably a fall or something? anyways, me being me i shall jump to conclusions that it is the cause of the issue (one ear works and one doesn't when on bluetooth, works fine when through the 3.5mm jack which goes pretty much straight to drivers)
ok writing this, tested it with continuity and it's fine, resistance at 1.8, touching leads it shows 0.9, it's a cheapo ebay meter i got for no money, but it's in the ballpark of working... damn.
ill attach an album, but any tips on troubleshooting it would be awesome, as I'm still rather green at it.
i am really hoping there isn't some jelly bean bit blown under the earphone jack, as that would be a bummer to remove... Can't find where driver signal comes from bluetooth, when audio cable isn't plugged in, as the pin that goes to driver, leads straight to 3.5mm female connector.
well ok figured it out, didn't need help but will post this anyways, been looking for something more complicated than it actually was. red circled the bodge, it works fine, tested resistance and continuity to see if theres diode or resistor between them but it's open circuit as far as my cheapo meter can tell and with bodge both seem completely identical. no idea what broke in the connector or what, but I don't feel like desoldering it to see, it seems like a lot of work

very strange issue but that's 150£ worth of headphones for 40£, sister will be happy and can stop being delusional about wanting beats hopefully...
Journey end. short album of the pictures of the board here
http://imgur.com/a/Zdoxf hopefully it might come in handy to someone someday.
i did redo the white/red wires for driver, had tacked it back on to test, they have appropriate joints now. sometimes only fix you need is the most simple one i don't check for i guess.
Headset is good for price new, amazing for 40£, if anyone wondered. Built well and all that.