Dim headlights, radio.....

[mychking]

I have a few issues: 1st my 2000 s80 started running rough all of a sudden. I just got an oil change and tune-up. My husband seems to think its from the deep snow we've had to drive in recently. The car is actually putting. Also just recently my radio and dash lights are very dim somedays they seem to work perfectly fine and others they don't. If anybody can just steer me in the direction I need to start checking I would greatly appreciate it. thanks for your time.