Low coolant light

I have been having trouble with the low coolant idiot light on my 99 GTP for many months. Actual coolant level has never been a problem. At first it was intermittent then constant on. I removed and cleaned the sensor which resumed intermittent behavior for a while but returned to constant on. I concluded the sensor was bad and today replaced it. The idiot light remains on constantly.

I have read archived postings, particularly pinkcookies26 9/15/2009 (almost made this posting a reply to that one), gtpguy 5/12/2004, and helicopter23 6/25/2009. Apparently this sensor is a chronic problem and it may not be worth spending more time on.

I flushed and filled last year with Prestone DexCool. The archives imply that Prestone DexCool can cause the sensor to trigger. Could this be my problem?

yes, you hit the nail on the head. GM sensors seem to have an issue with prestone dex-cool.

I too had that issue immediatly after a coolant flush. Replaced sensor, ok for a short time, back on again. Then one day driving it shut off and has been fine since....?

If your ok with it, you could just un plug the sensor.

I flushed and filled last year with Prestone DexCool. The archives imply that Prestone DexCool can cause the sensor to trigger. Could this be my problem?

Last time I checked the credible archives were referring to primarily Prestone Extended Life 5/150K coolant and not Prestone's licensed version of GM's Dex-cool but I guess it is possible to have the same issue.