What is causing my 2003 Pontiac Bonneville's air conditioner/heater not work?

[Emily Anderson]

My Bonneville's air conditioner/heater doesn't always work. Most of the time, it doesn't work, and it's pretty miserable. Sometimes, when I go over bumps, the air starts working. Some people tell me they think it's the wiring, but I'd like to know more in depth what's wrong before I spend tons of money on fixing it.

 

[nothinbutnet70]

mine did the same thing only i found out it was my blower motor.i just tap mine with a hammer after i start it in the winter to have heat.