I am not sure if this is a problem or not but on my wifes 99 4.0 cherokee the fan comes on runs maye a minute then shuts off for 30 sec and then on for a min. I dont think this thing can be efficient enough to cool the engine that quick. But should I be concerned.

I have had two jeeps, a 97 cherokee and now a 98 cherokee. Both have the same fan pattern. I notice many of the later model chrokees do it as well. DO NOT WORRY, it is not a bad thing and is quite common for your jeep. I have had it checked out by a mechanic and though abnormal in general, it is of no harm. In addition, my last 97 cherokee did it for as long as i owned it and never gave me a problem. Hope thats some comfort.