Which is the Coolant Temp Sensor?

On the M103 engine in my 88 300E there are two coolant sensors near the rear of the cylinder head on the drivers side. I know that one of them is crucial input to the fuel injection system and can cause an ill idling or no idling engine. Which is the sensor for the FI, the rear one or the next to the rear one?

Does anyone have the resistance table for this sensor. I am not at home and won't be able to look in my CD until this weekend.

Thanks for any help that anyone might offer.