So I just found this blue thing that looks like a sensor under the battery tray, it wasn't connected or anything, just lying thing there
here's what it looks like:

 

Looks like you would dip it into a thing of glue...

Nice carfone btw

 

ok, nevermind I figured out what its for, the original factory batteries had twist on cap things on them and you screwed that sensor into one of the them for when the system does that cool check thing

 

Its for the battery level sensor, when you used to have the old Maintenance batteries, it checks the level of the acid and if its to low it triggers the warning light in the dash.

EDIT: lol I should read the entire thread.