Your coolant light is a known problem. Not sure what year your car is but I know of 2 99 mystiques that the light kept coming on or staying on. It is the sensor in the resvior. It will only get worse now. Dealer replaced one under warrenty which fixed it. I think the other one was jumped to stop it from being on. Not sure though. Good luck finding your other problem.
Green 2000 SVT #1166
mods-K&N open air filter & Custom heat shield, Custom y pipe and 30 in resonator,DMD, arm rest heightened
http://www.geocities.com/savinoss/Cars.html other cars-89 sable 197000 miles and still going-Wifes car 99 Mystique V6 5 spd
