Originally Posted by kirasir
All that's needed is to wire one of these into the OBD harness or the fuel pump relay:
The OBD harness/port is probably more convinient as one would only need the RFID token to activate the OBD port vs using it every time to start the car if the circuit is wired into the fuel pump/ignition.
So I just looked into this and thought about it.
What if you could do a combination of both this and the glovebox idea?
1. Tap into the DC+12V line via the OBD fuse.
2. Ground the RFID unit to the ground bolt in the fuse panel.
3. Hide all of this behind the glove box area.
4. Lock glove compartment.
I've got fuse taps that I've used to tap my dashcam directly to the fuse box so this whole install should take 15 mins to be honest. Only downside to that is you'll need to carry your RFID keyfob with you all the time but it'll be more secure since they can't just pull the wires out of the RFID unit and bypass the RFID unit to the OBD port. If these guys are stealing cars like this, I'm fairly certain bypassing the power on the RFID unit's not hard at all. However access to a physically locked glove compartment's going to be a lot harder.
Also by tapping into the fuse box as opposed to splicing directly into the wiring, it's external to the BMW's electrical system so warranty won't be voided. (plus you can easily remove it before bringing it in to the dealership)