Mike’s Z3 - Retro Aircon + Cruise etc Project

MickyG

Dedicated Member
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Nov 9, 2025
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28
That is not exactly true. There were at least two (possibly more) changes to the DME and other modules over the build period, as I have learned to my cost.
From 2000-on there was 'canbus' added to provide 'modern' electronics to quite a few wiring functions.

But it does seem that all of the 'normal' electrical stuff is common to all and the general looms are generic.
Interesting.
My donor is/was a 2001 M54 2.2.
I’ve encountered changed plug styles on the Aircon - hopefully nothing more! (Though I won’t know until it is pressurised to allow the compressor and fan to kick in).
The M seats seem to have a different wiring set up (not just plugs) but because they are heated I’d like to add that functionality to my car; I am hoping I can swap the seats onto my own bases and then wire up the heated elements separately.
This probably concerns me more than the Aircon as a project.
But again Google and this forum are my friends🙂 and I’ll get there.
 

Nodzed

Zorg Expert (II)
Supporter
British Zeds
M Power
Joined
Feb 18, 2016
Points
231
Location
Forest of Dean, Gloucestershire, England
Model of Z
Z3M Imola and Z4 (e89)
Hi Ian
Lucky you with factory fitted options🤗
Cruise was very easy to fit: Aircon will be much less so!!!!!!!!
I’ve managed to get hold of a cheap Z3 2.2 Special Sapphire Edition with Blue/Black M seats (are they exactly the same as the M - does anyone know for certain?). I do know they are much better than my standard seats for support and comfort and will go with my Atlanta Blue car.
The deal clincher was it having Aircon, and a set of Z3 factory staggered Style 32 wheels (my preferred option on a widebody 2.8).
I’ve removed the Aircon already - and am pausing, swallowing hard, and summoning up the courage to tear my beautifully trimmed interior out to be able to swap it over!😳
If you have M sport seats they are not the same as M seats.
 

Pond

Zorg Guru (III)
British Zeds
Joined
Dec 26, 2016
Points
144
Location
Spaldingski, Lincs
Model of Z
Z3 project
My donor is/was a 2001 M54 2.2.
I’ve encountered changed plug styles on the Aircon - hopefully nothing more! (Though I won’t know until it is pressurised to allow the compressor and fan to kick in).
The M seats seem to have a different wiring set up (not just plugs) but because they are heated I’d like to add that functionality to my car; I am hoping I can swap the seats onto my own bases and then wire up the heated elements separately.
So your 'car' is a 1999 M52 2.8 and the 'donor' is a 2001 M54?
From what I have gathered if a Z3 has ASC (auto stability control) it will be be on the analogue wiring; if it has DSC (dynamic stability control) it will be on the newer 'digital' wiring loom with a different DME (and ECU I think). I may be wrong but it does seem to be an easy way of telling.

I have full 2000 year and 2001 year wiring diagrams on PDF if you need them emailing. 95% are the same for each but the 5% are always the ones you need!
 

MickyG

Dedicated Member
Joined
Nov 9, 2025
Points
28
So your 'car' is a 1999 M52 2.8 and the 'donor' is a 2001 M54?
From what I have gathered if a Z3 has ASC (auto stability control) it will be be on the analogue wiring; if it has DSC (dynamic stability control) it will be on the newer 'digital' wiring loom with a different DME (and ECU I think). I may be wrong but it does seem to be an easy way of telling.

I have full 2000 year and 2001 year wiring diagrams on PDF if you need them emailing. 95% are the same for each but the 5% are always the ones you need!
Yes please to the wiring diagrams: particularly the seats.
Do you have the earlier 99 diagrams too?


Many thanks
 
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Pond

Zorg Guru (III)
British Zeds
Joined
Dec 26, 2016
Points
144
Location
Spaldingski, Lincs
Model of Z
Z3 project
Yes please to the wiring diagrams: particularly the seats.
Do you have the earlier 99 diagrams too?
Many thanks
I don't have 1999. It may not be the best idea to put your email address on a public website. Anyone can access this site. I have made a note of the address if you want to edit.
 

MickyG

Dedicated Member
Joined
Nov 9, 2025
Points
28
If you have M sport seats they are not the same as M seats.
This is a subject I would like to understand in more detail.
BMW use the M badge quite loosely.
In terms of seats I have physically seen 3, but possibly 4 different specifications.
Standard
Sport
M Seats - as in Z3M. } =
Sapphire Edition “M Sports seats” } =

My uncertainty lies around the Z3 2.2 Sapphire Edition.
This was a run out edition usually offered by BMW with a 2.2 engine with an option for a Z3M stylised interior with M Sports seats and colour coded door cards, handbrake, gear lever gaiter and steering wheel.
These seats are not Sports seats: the bolster designs and seam stitching matches the Z3M.
But does that make them the same?

This is my Sapphire Edition interior:

IMG_7138.jpeg


IMG_7110.jpeg


The seat base stitching and upper bolster design are, I believe, the same as Z3M seats.

Nodzed, are you saying these seats are not “The same” as those in a Z3M?
 
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MickyG

Dedicated Member
Joined
Nov 9, 2025
Points
28
A quick test fit of the condenser and pipework confirms they all fit.

IMG_7425.jpeg

Whilst researching this project it’s become apparent the driers are non re-usable as once the system is open to air they quickly saturate, so I’ll order a new one along with new seals throughout the system.
Also I’ve noticed one of the aluminium connections between the condenser and pipe to the drier at the front of the car is badly corroded. I’ve cleaned them up, but if the joint leaks, the cost of de-gas and re-gas means I’m better off buying a new condenser and short pipe from one of the OEM suppliers to BMW.
 

Pond

Zorg Guru (III)
British Zeds
Joined
Dec 26, 2016
Points
144
Location
Spaldingski, Lincs
Model of Z
Z3 project
Yes drier/receivers should be changed if exposed to the air for more than a few minutes.
The most important thing to remember with a refrigeration system is that moisture is the enemy. Air contains a lot of moisture, so keeping air out as much as possible is a wise move. When you have the system tested and filled with R134a make sure you ask whoever does it to give it a very good 'vac' (evacuation). Even the smallest amount of moisture can cause huge problems.

I would offer to do it for you but I don't have the equipment anymore as I 'hung up my gauges' a good few years ago now.
 
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