I stored the radio to my ERBL in a cold storage this winter and now I'm worried it's broken...

I tried pairing my erbl with a friends radio instead and it worked.

The errors I get on my radio is that the car gives me the red light (equals low voltage on transmitter?) - even if I have fresh batteries. And - when trying to pair the transmitter with mobile app via bluetooth - the blue light is there on the transmitter but it can't be found by my phone. I've tried restarting phone/BT but no change so I suspect it's related to the other issue.

So - is there anything I should try out/is there a chance to repair - or do I have to buy me a new transmitter? (Which obviously is quite expensive..!)

Thanks for your help!