It looks like my car has 3 coolant temp sensors. I need to know what each of them do, so that I can check and replace them if they are bad. Below is a picture of my car's 2.3 8v engine's front side(1st pic - thermostat housing, 2nd pic - engine fan)
I have numbered parts that look like sensor. The sensor #1 is more complex. It has 4 wires coming to it. The others just have 1 wire.

Thanks

Attached Thumbnails

 

__________________
1989 230E, 8v, 166.000 km, updated to 94/95 trunk & hood
2002 Daewoo Nexia 50.000 km
Sold:
1987 VW Jetta GLE 16V, Recaro seats
1982 Volvo 240 DL (lovely car!)
and few more american cars.

here is a third temp sensor

Attached Thumbnails

 

__________________
1989 230E, 8v, 166.000 km, updated to 94/95 trunk & hood
2002 Daewoo Nexia 50.000 km
Sold:
1987 VW Jetta GLE 16V, Recaro seats
1982 Volvo 240 DL (lovely car!)
and few more american cars.

i think the 4 pin sensor is linked to the fuel injection system and
ignition system-that is what it is on my 1993-190e-1.8 litre uk spec 1993 car.

sorry do not know wht the others are.

But I do remember you have a 230E? (Euro?)

If that's an M103 engine, the #1 picture is the 4 pin temp sensor which the previous poster accurately identified as involving the Bosch fuel injection system. The sensor feeds the system info, and your fuel injection system reacts accordingly.

You should also have a two pole, and a single pole temp sensor. The two pole is the ACC emergency cutoff sensor, that kicks in the high aux fans at 105deg?, and shuts off the AC compressor at 115deg to prevent damage.

The single pole temp sensor relays the temp to your dash, and nothing else.

G'luck :p

__________________
-Paul-
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi