in fact, some of the cable colours I have do not match those on your list... getting very confused now!

First of all use your meter to check for 12V on pin 17 or 18. That will tell us if it is plugged in to the power.

Next we need to find the BITII 54 pin pinout and see if you have that one instead.

OK I need to do some work now (pesky job) but look here. Search for U407. There is the various sockets for the BITII 54 pin version. Have a check and compare with your setup. Compare and contrast with Io1157 Telematics control unit. You may want to start cutting and pasting some of those tables (green table looking icon) into excel with notes on what unit they came from, as it may assist you when you come to swapping pins around. It's a lot of pins to remember.

Right, this is what I have in the 54 pin plug with regards to colours:

1 yellow
2 empty
3 yellow
4 empty
5 black
6 yellow
7 empty
8 empty
9 red
10 white red
11 white green
12 empty
13 empty
14 empty
15 white yellow
16 empty
17 red yellow
18 red yellow
19 black
20 empty
21 shield
22 white green
23 empty
24 empty
25 empty
26 empty
27 empty
28 empty
29 green
30 black
31 empty
32 red yellow
33 white green
34 red
35 violet white
36 brown
37 black white
38 vlack brown
39 brown
40 empty
41 empty
42 empty
43 empty
44 empty
45 empty
46 white
47 blue brown
48 blue black
49 empty
50 empty
51 white brown
52 grey red
53 empty
54 brown

will try and get the meter on it now.

thanks

i can find three versions of U407 - but it doesnt give the cable colours? And none of them sound like they will match what I have at the moment.

I cant find anything on I01157?

Sorry

OK, 17 and 18 both at 0v when power is on - that will be the problem then!

Where do these looms run? I can follow it to the back seat, then it disappears under the floor....?

This is the adapter part number you need.

84.12-0 308 375 DB25 to 54-pin ULF/TCU plug adapter

Forget about that existing 54-pin plug in your car. I have no clue what it was for, but your old phone was connected to the DB25 plug, so that is the plug that is hot and able to support a TCU.

Also, if your phone box was a Motorola, you do not have to worry that you had a BITII system. First, the BITII was made by Siemens. Second, it had the 54-pin plug.

Get the adapter PN above to connect your TCU, and you will be all set.

thanks Brian, I just rang BMW for that part and they say the part number does not exist?

Sorry
Sam

could it be this number 2 on here (not sure which variant!)

RealOEM.com * BMW E53 X5 3.0i Single parts f Cordless lugga. compartm.

DB25 to 54 pin is not available in the UK. You could ask nicely at Cooper BMW parts if they can add it to their system but don't hold out much hope.

It's also close to £60.

You could make one if you are any good at soldering.

I have no idea where your particular car goes, but I'm thinking you are looking at a dash-strip down to find and wire in the audio, power, ibus, mute blah blah... I can't believe you have a loom laid but it is not plugged in! Is the fuse in place? The colour codes for the wires is on the page with the shcmatic for the U407. You have a typo in the telematics part number.