Recently my Jeep liberty's electric fan started vibrating the whole car and it makes a lot of noise only when I turn on the A/C. I noticed that my the fan works when its supposed to and I've never experienced any problems with it. Now I can't turn on the A/C because each time the noise gets worse and worse. What could the problem be if the fan works good? It doesn't shut down randomly, it just makes a lot of noise like it's hitting something. I hardly use the car and it barely has 22,000 miles. Please help.