is there an Antenna for the CB on there? one pic looks like it may have a center mast on the roof, but hard to tell. Run to Walmart and but a cheap Antenna to thread to the radio and see if that helps, sometimes the old antennas just quit.... you really don't want to hit the mic without a load on there, though.
if you know the radio is absolutely working and you aren't hitting anybody on 19, try some other channels.
-19 is always the "go to", but 17 is actually for North-South Traffic and 19 is for East-West traffic.
-Lots of overflow goes to 21-28 just to stay off 19 to have a convo.
-Jeepers and 4WD folks like to hit channel 4.
-Vanners tend to hit Channel 2 (If you have to ask...)
-Channel 6 is the superbowl, where you will catch a bunch of hooting and hollering from the guys running massive wattage or shooting skip. LOL.
The CB airwaves are pretty dead these days. I can run 100's of miles here on the SE coast without hitting any legit CBers actively talking to each other, but certain localities they are out there talking...logging trucks and guys at shipping docks are common. SE VA has pretty active airwaves.