I have a spare 7-button MID from one of the cars I dismantled and now that I have moved to a colder climate (Sydney Blue Mountains) I thought it might be interesting to fit it to see what the outside temperature is.
The 7-button MID (Multi Information Display) has time and date, outside temperature and a memo function.
Sure it would have been nice to have one of the OBC (On Board Computer) modules instead, but they are rare in a 318is and need a lot more work to fit I'm sure.
To fit the 7-button MID you can use some wires from the analogue clock connector, and some extra wires from the radio wiring and the climate control wiring. This gives full functionality including the change of brightness from the dimmer control.
You will need the MID, temperature sensor, and the MID connector and wires. Here's how you should wire it up:
18-pin MID plugSourcePurpose
Pin 8 (black/green)Climate control pin 8 (black/green)Start
Pin 9 (green/blue)Climate control pin 24 (green/yellow)Power (run/start)
Pin 12Temperature sensor (+)Temperature
Pin 14 (violet/white)Radio pin 5 (violet/white)Power (accy/run/start)
Pin 16 (grey/purple)Analogue clock pin 3Light switch (dimmer)
Pin 17 (brown)Analogue clock pin 2 (brown)Ground
Pin 18 (red/yellow)Analogue clock pin 1 (red/yellow)Power (all times)
To get the temperature sensor wire through the firewall, there is a bunch of wires that go through the passenger side (right hand drive) behind the glovebox and into the fuse box. You can use a knitting needle to push the wire through.
Access inside the fuse box is a little limited but I was replacing the fuse box in my car anyway because the plastic clips that hold on some of the wiring had broken off.
Replacing the top part of the fuse box is not a pleasant job, but is reasonably easy.
Undo the upper and lower large power feed wires using a 13mm socket. They are very tight and need a lot of force.
Working from the front remove all of the fuse sections and relays sockets. The fuse sections come out by pushing the plastic clip at one end outwards and pushing through from above at the same time. They need a bit of force and you may want to remove the end fuses. The relays come out by pushing a clip on the underside inwards. A mirror will help you see what you need to do.
Installation is the reverse of removal.