Parasitic draw....I know your pain
I completely understand your pain. I have an 05 330i ZHP with the same problem, although I do have an Dice Ipod adapter installed, plus angel eyes, they are not my problem.
Here's my problem.....I have the standard biz CD in my car w/HK, no nav. My radio while asleep runs my CD ejection motor. My amp draw ranges from 1.3 to 1.8 amps. I thought too I had a cure when I found a couple of wires in a bundle going to my BT module in drivers side trunk. But as of yesterday, I am back to square 1.
I am going to finish what I started before I found the wires, and that is to visit each grounding terminal with the car, roughly 9 locations and clean/inspect/reinstall each.
I have been troubleshooting this problem for 5 months, I have bought programming software/OBDII/Flukes/Amp probes/etc. I will figure this out.
Here is a note that I have learned from other forums....is that BMW knows about parasitic draw...they recommend that you just drive the car daily...lol....they also know that it can be several different components that cause the draw....it can be the IKHA/heater controller, radio, drivers headlight switch...my point is rarely is there a common component between vehicles...check out the X5 forum, it is quite common on those.
So my recommendation is to check ALL the grounding points, and harnesses for chaffed wires. I will be in touch. FYI, I can read schematics, use a Fluke, interpret data...but I am not an ASE certified car doctor.