So my buddy had a BOSS 1500 low profile sub/amp that he bought awhile back and he wasn't going to use it so I picked it up from him for $50.. and i'm having some difficulty installing it.

the unit turns on and everything but I can't get it to make any sound.. i checked the wires and everything several times.. I don't know where to go now.. im probably just missing something stupid. I've turned on the "sub-on" settings in the headunit and i've messed with settings on that already...

Well here's my setup.. thanks for any help ya'll can provide

93 F-150 Flareside
Headunit: Alpine iDA-X303
Sub/Amp: BOSS 1500 Low Profile
The rest of the truck is fully stock except for some engine upgrades
All electronics are stock except for the headunit