Although I can't say for different/later models, I found fitting an OBC t=

• my 1986 525i a simple job as long as you have a wiring diagram such as = in the Haynes manual.

In my car, the clock was removed and replaced by the computer display/key= pad unit, a multiway cable connected the display/keypad to the OBC contro= l unit (brain) in driver's knee panel below steering wheel. The `OBC cont= rol unit' is then connect via another multiway lead to the back of the in= strument cluster (to tell it the speed/consumtion/mileage etc..)

Out of the OBC control unit there are a few other wire, this is where the= wiring diagram came in, matching the colour coding of the wires and labe= lling them I was able to find the green wires in the dashboard for the CO= DE immobiliser which are connected to the OBC control unit, also, the add= itional horn output wire from the obccu, the outside temperature sensor w= ires, the permanent and ignition controlled 12v supply and an earth.

It all works fine, but if you take one out of another model, you may need= to replace the model-specific coding plug in the OBC control unit.