Jeep Repair: Coolant Sensor Bad, jeep grand cherokee, jeep owner

Question
Dear Ron:  I have a 1997 Jeep Grand Cherokee.  For the past 2 summers (only summertime), the inside console panel flashes "Coolant Sensor Bad" intermittently (mostly at higher speeds).  My Jeep Dealer replaced the sensor at the overfill bottle 2 and 3 times but the warning signal continued to flash.  After that Dealer's technician AND another Dealer's technician went through the Jeep Completely and could find no reason for the warning signal, they "determined" that I must need a new Computer Brain at the cost of approx. $1,000.  The warning signal DOES NOT come on AT ALL during the winter months.   PS:  It seems that the very first replacement Coolant Sensor did not fit "properly" in the overfill bottle.  Should I maybe consider replacing Both the Overfill Bottle AND the sensor...before Replacing the Brain ?  Please help.  My jeep has had many "gremlins" and strange problems...I'd be happy to share any of my experiences with someone else to help another Jeep owner :D.  Thanks, in advance. B.

Answer
When it comes to electronics, the dealers "got ya", it seems. I have never heard of the problem thus can't really direct you one way or another.
If the only thing the computer is tripping is this particular sensor and the Jeep is running at the proper temperature, I guess I could stand to stare at it but do whatever you think.