radaitor fan not turning

The fan is doing some crazy stuff... sometimes it works sometime is doesnt

Is the car overheating? Are you sure it just does not kick in until it is supposed to according to the radiator temperature? Mine is doing the same but it may just be because of the changes in the seasons. I'll be watching replies with interest.

Try fan relay, it is located behind the passenger front headlight. There are three relays there, one for A/C, the other for gas pump, the other one controls the cooling fan on radiator.
Also, check your heat sensor, it might be reporting wrong temp.

Ok heres my experience with my van. I have the 3.8 liter and had some problems with it over heating. I had to replace the fan relay behind the pass. side headlight and I had to replace the temp sensor thats CONVIENENTLY placed underneath the throttlebody. (If your not a halfway decent mechanic PAY someone to replace that its a pain.) The only way that the fan will run is if I keep the defroster on. Try it it might be your problem.