Need help with wires on my 92 SL1

On the back of the engine on my 92 SL1 ,right above where the tranny bolts
to,the are 2 sensors of some kind.
One has 2 wires going to it(one of them yellow) and the other has just 1.
Which one has the 2 wires going to it?.... thanks for your help?(what are
these 2 sensors anyway?)..........Mark

 

Sensor with Yellow and Grey wires, Engine Coolant Temp Sensor.
Single Wire, being a 92', is probaby the sensor for the ECT Gage.

 

Top sensor with one wire - your gauge indicator that essentially
measures engine head temperature.
The bottom sensor - a VERY important issue! It is the computer's
engine coolant temperature sensor. Its the one with two wires. THIS
item only costs about $9 at AutoZone, but IT is responsible for half of
the Saturns you'd see in the junkyard.
This sensor goes bad, then the engine computer runs too rich, the fan
motor won't switch on and the car develops chronic overheating problems
(because the computer thinks the engine is very cold WHEN it's very
HOT.)
When this sensor goes bad, the car will not pass an emissions test and
will idle at about 1200 while stopped and 1700 rpm while car is moving.
At about 60degrees w/engine cold, the sensor should measure about 4k
ohms resistance. At 200degrees (engine hot) the sensor measures about
100 ohms.
Its hard to check this sensor while its in the engine... I made my own
connector from a cable harness from a dead tv set (little inline plug
inserts).
I just bought my second SC2. I got a GREAT deal on it was because the
original owner's "shade tree" mechanic didnt know what was going on
with it. As I'd had experience with this sensor problem with my first
Saturn - I realized when I test-drove it exactly what was going on!
This applies to SC and SL Saturns from 91 to at least 96.

 

Thank you very much.That did alot to clear things up....I owe ya one... Mark