I did a test run with the D3, only power installed and no remote turn on wire hooked up, so my amps were off, and I drove from my house to Sears (about a 15 minute drive) with the unit on the whole way. When I came back from Sears (10 minutes in the store), I put the key in and put it in the on position to prime the fuel pump. I knew immediately what happened... pump started to fill, normal ding, lights dim a little and DAMNIT! Battery is dead. Click, click. I unhook the harness to the D3 and still click, click. I pop the trunk (its a bmw, battery is in the trunk) and get ready to have to jump the battery, and about 30 second later the lights come back a little. It finally starts.

Why?! Why?! After all this cutting and mangling of my dash to make the double-din mounting kit fit, I learn its going to drain my battery?

The car is an E39 BMW 540i. The battery is fairly new (3 months perhaps) and is still good as far as I can tell.

I'm using a (I believe Metra brand) harness that hooks into my where my factory radio did. I only hooked up power, ground, illumination and one other one that I'm now forgetting.

Also, how do you turn the unit completely off while you're driving?

Depending on what year and stock system you had in your car you may have a factory amp for your speakers, if so your metra adapter may not be turning the stock amp off and there for killing your battery. I would say go back and check your connections.