Sounds like a wiring problem.  Speakers typically go dead if one of the
speaker wires is shorted to ground.  You've already told me the radio
operates other than the fact you have no sound.

The most common problem with the clock is that there's an internal
problem.  It's easy enough to check for proper input.  You've got one wire
for ground, one for constant power, one for ignition switched power, and
one signal wire from the lamp switch (which controls whether the clock
dims).

The most common problem with headlamps is the bulbs themselves, even if
both are out.  Start there.  Then, if the bulbs are okay, check things
like relays, switch, and grounds.

The bad news is that if there's a common cause for all the items, it's
likely chafing wiring somewhere behind the dash.