Your service technician is going to be primarily interested in the symptoms
and won't expect you to be able to tell him the cause of the problems.
It sounds to me like you have two separate issues. First, it sounds like
you have a problem with the radio itself. Unfortunately, the radio
warranty is 3yrs/36k miles, so it won't be covered. The fan speed
changing may be normal, especially if several high load items are turned
on. The alternator's ability to deliver voltage and current is limited at
idle, so if the lights brighten a little and the fan speed kicks up a
little when you step on the gas, it's possible this is normal. Similarly,
it's also possible that you actually have an alternator or battery problem.