Originally Posted by marksto
Had the same "coolant sensor" problem on my '94 a few years ago. It was intermittant and drove me crazy for a long time. I removed the sensor and inspected it, cleaned it, etc.. to no avail. Save your sanity - go to the dealer and buy a replacement like I did.
Every time this topic comes up it's the same story, some say to inspect and clean the unit and others say to replace it period.
To inspect and clean the unit should take about 10 minutes, it may save you a trip to the store and a few bucks and give you a feeling of slight accomplishment, changing every part that you think is bad may work fine, but Jeeps are pretty durable and some items are cleanable in some cases, example:
I clean my IAC and the results are great
I clean my O2 sensor and the results are great
I buff the haze right off my headlights with great results
I clean the coolant sensor with great results.
I have also changed about 20 other bad parts on the truck including axles and pulleys, starters, alts, injectors and a ton of stuff that was unsaveable.
It doesn't hurt to try to clean it and check the connection before replacing it.