My Jeep Grand Cherokee Limited goes through periods where the ABS light comes on along with the break light and the check engine light. When that happens, my speedometer will not work nor will my cruise control work. Sometimes the heater fan will also stay on after I turn the ignition off. This happens randomly. Usually it is humid or wet outside when it happens, but not always. I have had the O2 sensors replaced, and been to mechanics quite frequently to try to get this resolved, and so far it has cost me a small fortune. Thankfully, when it gets real cold, or hot and dry, it will return to acting normally. What could be the cause of all of this? Any and all help is truly appreciated!