Alot of the little intermit issues that drive you crazy can be fixed.Switches must be exercized.Why does the little brake switch work for so many years yet that under hood light needs a couple of flips before it functions correctly(until the next time).The better switches make contact at a slight angle as to scrub the contacts clean when used.Your parents always said "don't twist the knob off that!!"You should!!.300z's are bad about radio static when you move the volume control.With the car off.Spin the knob from min to max until you get bored.If it slides--slide it. if it clicks--click it.I work the over head light door switch by pushing it in and letting it pop out --nice fresh ground path (battery disconnected,don't want to do a fuse test!).When was the last time you worked that dimmer switch for the dash?.This works on all devices TV's home stereo,Work them all.Let me know what you fix!

Absolutely right. Worst thing for anything mechanical is lack of use. If there is any access to those radio switches and rheostats, static can often be eliminated by spraying with contact cleaner. Victor.