The battery temperature sensor on a 2007 Dodge RAM 1500 4X4 is located in the negative battery cable. It is a small black sensor that is attached to the cable near the battery. The sensor measures the temperature of the battery and sends this information to the vehicle's engine control unit (ECU). The ECU uses this information to adjust the charging rate of the battery and to protect the battery from damage.
Specific Location
Passenger Side Battery Terminal