Mike’s Retrofit Aircon Cruise Heated Seats ++

[Eddie Zedder]

I found yet another one this afternoon - hiding under the M seat bases: it runs up the back of the seat, not into the seat bases. It has two thin black wires - anyone one know what it is for?

These were fitted to later model sport & m seats, It's a cut off switch, in the event of a rollover it opens and cuts power to the seat motors. It plugs into the loom that's attached to the seat frame, the plug won't be present if it is an earlier seat frame.

Apparently a driver in the USA had a lawsuit against BMW. He rolled his Z3, damage to the seat switch operated the motors pinning the driver against the steering wheel, hampering escape, hence the subsequent fitting of the cut off.

 

[Pingu]

These were fitted to later model sport & m seats, It's a cut off switch, in the event of a rollover it opens and cuts power to the seat motors. It plugs into the loom that's attached to the seat frame, the plug won't be present if it is an earlier seat frame.

Apparently a driver in the USA had a lawsuit against BMW. He rolled his Z3, damage to the seat switch operated the motors pinning the driver against the steering wheel, hampering escape, hence the subsequent fitting of the cut off.

I can go out to play, as I've just had my education for the day.

Many thanks

 

[MickyG]

These were fitted to later model sport & m seats, It's a cut off switch, in the event of a rollover it opens and cuts power to the seat motors. It plugs into the loom that's attached to the seat frame, the plug won't be present if it is an earlier seat frame.

Apparently a driver in the USA had a lawsuit against BMW. He rolled his Z3, damage to the seat switch operated the motors pinning the driver against the steering wheel, hampering escape, hence the subsequent fitting of the cut off.

Many thanks for the enlightenment
One less plug to worry about!

Do you know what this on is?

This was hidden under the carpet beneath each seat?
Is it airbag related?

 

[Eddie Zedder]

Many thanks for the enlightenment
One less plug to worry about!

Do you know what this on is?View attachment 355603

This was hidden under the carpet beneath each seat?
Is it airbag related?

I think they maybe for the seat belt pretensioners but not 100% sure.
My Zed is garaged up at the moment but I will take a look when I get the chance.

 

[MickyG]

I think they maybe for the seat belt pretensioners but not 100% sure.
My Zed is garaged up at the moment but I will take a look when I get the chance.

It’s not the seatbelt pretensioner - that has a purple plug on it and is used by all Z3s. T
The spare plug I’m showing must be for something that is not run-of-the-mill spec.
I’ll post the wire colours tomorrow: but without knowing what it’s for it’s difficult to look it up via a wiring diagram.

 

[MickyG]

It’s not the seatbelt pretensioner - that has a purple plug on it and is used by all Z3s. T
The spare plug I’m showing must be for something that is not run-of-the-mill spec.
I’ll post the wire colours tomorrow: but without knowing what it’s for it’s difficult to look it up via a wiring diagram.

The wire colours are:
Drivers side:
White/yellow
Purple/blue
Brown/orange

Passenger side
White/
Purple/blue
Brown/orange

Any ideas?

 

[MickyG]

My Z3 came fitted with a hideous (to me) Silver fascia multi-light flashing after market radio.
In my haste to dispose of it, I’ve now left myself slightly 🫤 confused - (not difficult these days)

I guess these two plugs were for the radio?
I say guess, because it had an after market plug spliced on

…..with much thicker wires: yet they are spliced onto thin wires to the next plug:

Could this be the plug that went into my “Disco lights” radio?”


Then if this is the aerial plug ?

What is the thick
cable and small white plug for?

Again, any ideas?

I’m now ready to button up my centre console to finish off the whole retro swap, but just want to be sure these plugs are for the radio only - I will have to come back to them in the future once I’ve decided what will replace the single DIN radio.

 

[Tony Francis]

The small white plug under the main radio connector is the CD changer control connector. On an original radio there is a matching socket that enables the radio to operate the CD changer if fitted. The other end of that cable will be in the boot but maybe hidden behind trim if a CD changer was not originally fitted.

 

[MickyG]

After going through my wiring umpteen times I finally felt I had it in place to make everything work, and more importantly, to feel confident enough to hide all the surplus wires/plugs that were always there but hidden previously.

I then decided to fit all the switches to their respective plugs and run tests on each switch/light etc.
Hey presto it almost all worked!
Seats moved up/down backwards forwards.
Aircon buttons all lit up (I can’t test it until it’s re-gassed), and heater controls all worked.
The heated seats both worked.
The analogue clock worked - as well as the digital OBC at the same time
Engine fired up first time, which was reassuring.

I do have two snags:
The airbag light comes on and stays on - I fully expected this as I’ve read on here that if you reconnect the battery before the airbag and its sensors are all connected it will throw a permanent fault: it should be straightforward to have it switched off at my local garage

Dash backlights.
This proved quite interesting: It started with no obvious back light to the heater control panel (it has two bulbs).
Then I realised there are one each for the cigarette lighter, ashtray and main headlight switch.
After much swapping and changing of bulbs I found all the wiring worked, but three of the five bulbs had blown.

Then came a shock - a quick google suggested the cheapest replacement bulb I could find was £14 each!!! X3 = £42!!! These bulbs are made as a sealed unit with a bespoke plastic molding to suit only BMWs, making them unique, and VERY expensive!

A lot more googling provided a much more palatable solution, and it all came back to this forum!
A member had shown in a previous thread that it is possible to snap the existing glass bulb out of the plastic molding and then remove the two connector contact pins that remain in the molding. Then source a capless T5 286 12v 1.2w standard bulb:

……. which have two external bare wires for contacts. By carefully bending the two wires down straight and feeding them through the plastic molding it makes an effective copy of the original bulb/holder that can be plugged into the original loom connector.

So I’ve ordered 10 for the princely sum of £3.99 - delivery by Friday.
Assuming the wires don’t break whilst bending and feeding them through the plastic molding it will be a very simple cost effective solution.

 

[MickyG]

The small white plug under the main radio connector is the CD changer control connector. On an original radio there is a matching socket that enables the radio to operate the CD changer if fitted. The other end of that cable will be in the boot but maybe hidden behind trim if a CD changer was not originally fitted.

Excellent, thank you. And yes the other end is hanging loose in the boot.
As I don’t intend to have a CD changer and can’t see future owners wanting to either, I’m tempted to pull it out (provided it’s not too difficult to extract).

 

[MickyG]

Not had a good day today.
I have a hacking cough, and cold which never improves anyone’s day.

The day started well enough. The pack of 10 tiny T5 bulbs arrived in this mornings post .
A quick test proved the bare wire connectors can be bent without breaking.

Left : as they arrived
Right: wires straightened out

But from there it went downhill.

As can be seen the wires are very thin and quite short. When I carefully fed them into the BMW molded case the wires were not long enough to act as spades to connect with the cars loom socket.
I’d say I have a lot of patience when it comes to fixing (it’s really playing) my cars. So I thought I’d solder the original plug’s terminals onto the bulbs- easy.

Well, no it wasn’t!

Despite trying for over an hour the bulbs’ wires would not take solder, and proved very fiddly trying to attach the pins. Even after I had two pins soldered on they would not press through the plastic without breaking off.
I had to admit defeat.
As I have a donor car, and the damaged Aircon matrix, with its heater control panel, I reasoned I must have 12 bulbs (5 per car plus 2 in the heater control panel).
After loads of testing I found 5 working bulbs - except the one that back lights the main light switch would not come with the sidelight switched on.
An hour later after testing the wiring (and bulbs again to be sure) and then trying to trace its original source I again gave up in frustration and switched all the lights off to save the battery.

Then as if to add salt to the wound I switched the ignition on, and lo-and-behold the b****y light switch backlight came on bright as a button!
Apparently BMW decided you need to be able to see where the light switch is in the dark before you can switch on the lights, so made it ignition activated. Harumph!

I’ve wasted so much time today………

(But if I can draw a crumb of comfort from my wasted efforts, I now have 5 working backlights and so can begin to put my centre console back together…….. when I can be bothered…..I’ve had enough for today!!