I needed new batteries so I finally got around to relocating the left battery to the rear of the truck. I moved the right battery to make room for a big air filter a few years ago. Now I know where the battery temp sensor is... under the left battery. I hope it doesn't need a battery setting on top of it to make the system charge right. I started it up after I got the cables all rerouted and the voltmeter looked fine but I haven't driven it yet. Does the sensor only reduce the charging if the battery is bad and over heating? TIA! Craig

 

Here is some information from a 2005 service manual...

BATTERY TEMPERATURE SENSOR

DESCRIPTION
The Battery Temperature Sensor (BTS) is attached to the battery tray located under the battery.

OPERATION
The BTS is used to determine the battery temperature and control battery charging rate. This temperature data, along with data from monitored line voltage, is used by the PCM (ECM Diesel) to vary the battery charging rate. System voltage will be higher at colder temperatures and is gradually reduced at warmer temperatures. The PCM sends 5 volts to the sensor and is grounded through the sensor return line. As temperature increases, resistance in the sensor decreases and the detection voltage at the PCM increases. The BTS is also used for OBD II diagnostics. Certain faults and OBD II monitors are either enabled or disabled, depending upon BTS input (for example, disable purge and enable Leak Detection Pump (LDP) and O2 sensor heater tests). Most OBD II monitors are disabled below 20°F.

 

Thanks much! Whatever happened to a simple voltage regulator? Craig