2002 Cavalier Radiator Fan Not Working

I have 2002 Chevy Cavalier 2.2L with approximate 80,000 miles. Last week while sitting at idle in the parking, I heard a faint pop and the AC started blowing hot air. I also noticed that the engine temp had risen slightly above the normal temperature.

When I checked under the hood, I noticed two things:

1)The radiator fan was not turning
2) The AC also began to cycle on and off erractically. I could also hear the RPM's surging up and down each time it cycled.

The next day I started the car and the radiator fan seem to be working. The AC also worked properly until the engine reached normal temperature at which point the radiator fan stopped working again. The AC cycling and RPM surges also returned.

While driving, the car seems to run fine. However, the car temperature rises and the AC blows hot air when idle or in traffic.

My problem is very similar to the one identified in the following post: http://www.chevroletforum.com/m_3913/printable.htm

One last detail: I have not seen the radiator fan moving the last few times I started the vehicle (even when cold) I also turned the fan manually. It is unobstructed and turns easily.

I have already replaced both the coolant temperature sensor and coolant sensor connector. However, the problem remains the same as before. Could it be the fan motor or fan relay? If so, I have a few questions.

1) Is there an easy way to check the fan without removing the connector? Especially since can't see how to remove it. I am also not sure that I can reach it either because the connector seems to be underneath the fan and recessed into the shroud assembly.
2) Where should I look for the fan relay?
3) Or am I completely off base?

Thanks in advance
Michael