what is going on ?

Steering vibration can be caused by several factors. Tire alignment out of tolerance, Out of balance tires, snow/ice packed into backside of rim, a broken cord inside of the tire, physical damage to tire OR rim. Warped brake rotors (Chrysler rotors are notorious for this) Faulty (leaking or damaged) shock / strut assembly, and/or strut bearing failure to mention a few. Have the tires inspected by a qualified technician (some tire shops will do this for free) OR rotate the tires yourself and see if the vibration follows tire location. Warped Rotors - LIGHTLY apply the brakes (level ground at a safe location - abandon parking lot ect) at 35mph to see if you can feel a "grabbing" sensation thru the steering wheel. Note that the only repair for warped rotors is REPLACEMENT ! Shocks/struts look for physical damage & fluid leakage....then after a drive check unit with your hand.... a "cold" strut is not doing it's job. (leaking internally) Hope this helps.....let me know