From what I've read so far on other sites, the Kenmore compactors' motor has two different windings for normal and extra pac. It sounds like the extra pac windings have shorted out on you. Probably need a new motor.

I have a Sears Kenmore Garbage compactor, i hit extra pack , which holds the leverage on the garbage to compress it more tightly, when I hit extra pac it started making a clicking noise like shorting a wire then I started smelling electrical and it was done, the compactor still works but however the extra pac does not, eveything works fine except the extra pac. WHAT THE HECK HAPPEN, CAN I FIX IT, I AM MECHANICALLY INCLINED, SOMEONE PLEASE TALK TO ME SO I CAN SAVE SOME MONEY THE TOOLMAN