coolant temp sensor

[aqua190]

1991 190e, 2.6. about halfway back on the cylinder head is a blue sensor with 2 wires. is that the temp sensor or the a/c emerg cut out? when i short the terminals, the a/c cuts off and the aux fans go on high. is this the sensor that normally tells the aux fans to come on @ 100c or is there another one? if so, where is it?

thanks

[A264172]

This one: http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1FX0MB1RS1IZ0MGPA4&year=1991&make=MB&model=190-E-005&category=G&part=Engine+Temp.+Sensor
controls the Aux. fan.
And one of these: http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1FX0MB1RS1IZ0MNC8Z&year=1991&make=MB&model=190-E-005&category=C&part=Water+Temp.+Sensor&appEngines=_any
controls fuel injection based on engine temp.

From the Fast Lane catalog (top of the page).

[aqua190]

the only one i can find is the blue one with two wires. i don't think i have one with three wires. if so, does anyone know where it is?