I feel like a complete DeeDeeDee. I figure it has to be under one of the seats, how do I get to it?

 

Under the rear floor.

 

It's located under the cargo floor.

 

Right near the spare tire.. A perfect location imo..
Away from the motor heat & adds a few lbs over the rear wheels..

 

the battery is in a great spot, unless you are hit really hard from behind(battery acid could be a spray issue) but then again, if you are hit that hard from behind battery acid is the least of your worries...... another possible issue-- punctured gas tank near main electrical connections.

 

Don't feel bad, I had to go the internet to find the battery in my wife's 3 series BMW.

 

A while back we had a 1996 BMW Z-3, well battery was supposed to be under the hood. Even according to the Owners Manual..

But it was a late 96, & battery was in the trunk, like the 1997s' came.... That was a surprise !!!
What a car tho.. Had that one for 10 yrs..

 

At least it not like the old Subarus. "The spare tire is where?!"