Where is theCollant sensor 99 Saturn sl1?
Although I specialize only in air conditioning, I recently had
the experience of having to address this issue. The coolant sensor
on this vehicle is located on the driver's side of the engine
block, just below the head. If you are standing in front of the
vehicle looking at the engine, it is just to the right of the
center of the car above the transmission. It is a very small,
single wire plug and, as I learned, corrosion build-up, which is
apparently very common on this sensor, will cause a number of fault
symptoms, including rough idling and hard-start. Good luck.