I have a 1999 D, does anyone know what the sensor under the battery is?

 

Battery Temperature Sensor. It uses the temperature to calculate the intake air density and target charging system voltage.

 

Battery Temperature Sensor

 

Damn it Widow...

 

Would this make the engine stall after 15 minuets

 

It's also used to control the electic fan. If you have one...

 

Yes it can because it controls the charging system and if it is malfunctioning it will throw your charging system all out of whack and cause it to stall once your battery isn't able to supply enough voltage.

Replace that sensor and that should be your fix!

 

The D would run Great for 15 minuets then stop like you shut it off. unplugged it and the D ran fine

 

That is because it is basically killing the charging system (alternator to battery) and when you unplug the sensor, it bypasses it and uses a factory setting.

 

Thanks for that information. Will order a new one. Will it hurt the D if I run without it?