Pressure switch under battery???

Helped my nephew change out his battery and cables last night. Curiousity got a hold of me when I noticed what looks to be a pressure switch of some sort underneath the battery with a wire running somewhere.

What in the world is this??? Also, he had a really weird rattling/grinding noise from time to time from underneath the vehicle towards the back. Replacing the wasted battery has made this noise go away, what's up with that???

Battery temperature sensor

Rockslut said:

Battery temperature sensor

Click to expand...

Agreed.

I don't think the battery was the cause of the noise, unless the fuel pump was having fits due to voltage. Up until 93 a ballast resistor was used to reduce the voltage to the pump during normal operation, so that is probably not the issue.