Mike’s Z3 - Retro Aircon + Cruise etc Project

MickyG

Dedicated Member
Joined
Nov 9, 2025
Points
28
That is mightily impressive. I know everything is possible, but I was expecting you to take a week, not a day.

Chapeau, sir

:thumbsup:
Thank you
But I think it could take a week to put it all back together!
And a month for testing (finding problems) and commissioning!!!!
 

1955Davidr

Zorg Guru (I)
Supporter
Joined
Apr 27, 2023
Points
86
Location
Fylde Coast
This is a great read, keep up the good work. I totally agree on the seat issue, my first Z3 had cloth seats and I could not get comfy in them, I had them refurbed with new foam and leather cover, then put the front spacer raising bolts in, I still have them, but still not right should anyone need some. Some time later I had a "poverty" spec 630Ci and the seats let that down. When I saw my current Z3 for sale the idea of sports seats appealed and have proved spot on and I am now completely comfy with them.
 

Pond

Zorg Guru (III)
British Zeds
Joined
Dec 26, 2016
Points
144
Location
Spaldingski, Lincs
Model of Z
Z3 project
There are just two more to find - the On/Off to the cabin switch and the fan in front of the radiator.
I’ve a delayed start tomorrow, but I think that will be when the hard work begins……..
The connector for the on/off and recirc switch should be buried in the big bunch of cables on the transmission tunnel under the carpet on the passenger side IIRC.
The electric fan is a 'dual purpose' (and should be two speed). It is to cool the condenser and also acts as a supplementary radiator cooling fan. There is a sensor that is plugged into the radiator (offside near the top) which controls the coolant stage and I think (think) links through to the a/c stage.
 

MickyG

Dedicated Member
Joined
Nov 9, 2025
Points
28
The connector for the on/off and recirc switch should be buried in the big bunch of cables on the transmission tunnel under the carpet on the passenger side IIRC.
The electric fan is a 'dual purpose' (and should be two speed). It is to cool the condenser and also acts as a supplementary radiator cooling fan. There is a sensor that is plugged into the radiator (offside near the top) which controls the coolant stage and I think (think) links through to the a/c stage.
Hi Pond
That is useful information- when I’m allowed to go and “play with my cars” I’ll have a look😁
 

BillyB

Zorg Guru (IV)
Supporter
British Zeds
Scottish Zeds
Joined
Jul 13, 2016
Points
155
Location
Edinburgh
Model of Z
2.8 Individual Roadster
What,s the car sitting in front of your project.
 

Peter1450

Zorg Guru (II)
Supporter
British Zeds
Joined
Apr 1, 2018
Points
104
Location
Bristol
Model of Z
Z3 3.0 Z4 Coupe
Afternoon Mike enjoying your thread , just a quick question while you have the dash apart, my wife’s 3.0 struggles to clear the far right of the screen but real oem seems to point to only the two pipe’s from the blower to the air outlet/ vents.
In your opinion is there anything that would cause this ie a pipe disconnected or something similar, TIA
 

MickyG

Dedicated Member
Joined
Nov 9, 2025
Points
28
Afternoon Mike enjoying your thread , just a quick question while you have the dash apart, my wife’s 3.0 struggles to clear the far right of the screen but real oem seems to point to only the two pipe’s from the blower to the air outlet/ vents.
In your opinion is there anything that would cause this ie a pipe disconnected or something similar, TIA
H ha : interesting question. As I was preparing my dash to remove it, a plastic elbow shaped piece of tube fell on the footwell floor. As a brief search I found it was/is a piece of the air vent tube the goes to the passenger side windscreen vent.
Obviously I can’t be sure that this is your issue, but on my evidence it is a strong possibility.
I’ll take a photo later after dinner.
 

Duncodin

Zorg Guru (IV)
Supporter
Joined
Sep 8, 2021
Points
163
Location
Pontrhydyrun - in Crow Valley
Model of Z
M44 FrankenZed
Afternoon Mike enjoying your thread , just a quick question while you have the dash apart, my wife’s 3.0 struggles to clear the far right of the screen but real oem seems to point to only the two pipe’s from the blower to the air outlet/ vents.
In your opinion is there anything that would cause this ie a pipe disconnected or something similar, TIA
I have a dashboard on my work bench. The pipes you see on realoem.

The two long fat ones are connected to the fresh air face vents at either end of the dashboard.

The two small pipes shown on realoem at either side of the diagram are for the little vents on top of the dash that point to the side windows.

The conduits for the demist is one big shaped piece of plastic kinda molded into the underside of the dashboard so not a seperate pipe. I dont see any way that one side could come loose.

In my mind the most likely reason is a blockage.

I'm not in the garage at the moment. I will be in tomorrow. I'll have a closer look and see if I can get some good photos for you.
 

MickyG

Dedicated Member
Joined
Nov 9, 2025
Points
28
Apparently I have other plans today ………🤣
And it was………… a day out shopping and a very nice lunch in Stamford (Stamford Country Lounge Cafe) - a cut well above the normal: thoroughly recommend both it and Stamford.

Today has allowed time for reflection assessment and a little doubt on my retro fit.
As I removed my own system there will small differences I noted and wonder how to deal with them.
I couldn’t resist a sneaky visit back to my workshop this evening for a little more assessment.

The two units compared:
IMG_7379.jpeg

IMG_7354.jpeg

IMG_7352.jpeg


Although not apparent in these photos the HVAC unit has additional supports over the Heater only unit.
The HVAC unit rests on these rubber mounts on the transm

IMG_7374.jpeg



These are not fitted on my tunnel: however the carpet has pre-pierced carpet to allow them to be fitted

IMG_7371.jpeg


A small detail to note is also the lack of a metal mounting point in the lower carpet cut out in the above photo.

IMG_7345.jpeg


There is a small rubber bobbin mounted on a metal stand in the donor car. This is the first item that is not there in my car. And it is spot welded in place.
Not an insurmountable problem. I can either drill out the spot welds and Tekscrew it to my tunnel, or make an extended bobbin mounted directly to the tunnel.

As suggested by Pond there are buried wires in the side of the transmission tunnel.

Does anyone know the wiring colour code for the Aircon On/Off switch?

Another bitter /sweet finding this evening is the wiring to the Aircon fan.
The good news is I’ve found the wiring tucked away in my car: the disappointment is BMW have changed the plugs🤨
IMG_7357.jpeg

IMG_7358.jpeg


The main electrical supply plug to the HVAC is the same shape as in my car but with extra pins in it: I’m assuming that is for the Aircon controls?

On a different subject, does anyone have heated seats in their pre facelift Z3?
My brief research of the swap of facelift seats in to my car suggests I may need to add a relay in the main fuse box.
Does anyone have an additional relay in their box?

IMG_7367.jpeg
 

Pond

Zorg Guru (III)
British Zeds
Joined
Dec 26, 2016
Points
144
Location
Spaldingski, Lincs
Model of Z
Z3 project
Well spotted that man!
Any guesses?
Clue: I built it 10 years ago.
I’ll add some photos, when I can find them!
Looks like a Marlin Roadster to me, based on some old Triumph??
 

Pond

Zorg Guru (III)
British Zeds
Joined
Dec 26, 2016
Points
144
Location
Spaldingski, Lincs
Model of Z
Z3 project
Afternoon Mike enjoying your thread , just a quick question while you have the dash apart, my wife’s 3.0 struggles to clear the far right of the screen but real oem seems to point to only the two pipe’s from the blower to the air outlet/ vents.
In your opinion is there anything that would cause this ie a pipe disconnected or something similar, TIA
It's unlikey to be a duct issue, as said they are solid moulded and can't move.
My guess would be the foam seal between the branch duct and the main air outlet (at the top). When I removed mine it was extremely 'crispy' and started disintegrating as soon as look at it. I bunged the lot back in and gaffer taped around the seal!
 

MickyG

Dedicated Member
Joined
Nov 9, 2025
Points
28
These are drain tubes are they not?View attachment 352265
Hi Synclare
That makes a lot of sense, thank you.
Now that you have pointed it out it all makes sense.
The HVAC assembly has tubular stubs that insert into the stubby tubes: and these tubes have grommet bases that pass through the transmission tunnel.
I hope the holes that these grommets insert into have press out panels like the bulkhead one for the Aircon tubes.
Many thanks - as it will be important to make sure the HVAC drains locate into these drains - otherwise I could have found a puddle forming inside my footwells!
 

MickyG

Dedicated Member
Joined
Nov 9, 2025
Points
28
H ha : interesting question. As I was preparing my dash to remove it, a plastic elbow shaped piece of tube fell on the footwell floor. As a brief search I found it was/is a piece of the air vent tube the goes to the passenger side windscreen vent.
Obviously I can’t be sure that this is your issue, but on my evidence it is a strong possibility.
I’ll take a photo later after dinner.
This may or may not be relevant to your issue, but the vent pipes are not totally attached to the dash. These two pieces fell out of mine whilst I was removing the dash

IMG_7386.jpeg


The triangle vent on the right you will recognise as the vent on top of the dash: whilst this may primarily direct an airflow on to the side screens, would dome of the air flow not impact your wife’s side of the windscreen?

Below is a view of the underside of the dash showing where the vent tube should be located

IMG_7381.jpeg


IMG_7382.jpeg

And with it in place
IMG_7383.jpeg


Looking at the main vent tube it also has a dimple pus on connection, so I think your wife’s problem could well be a simple failure of that connection. As I’ve seen they do fall apart.
 

Peter1450

Zorg Guru (II)
Supporter
British Zeds
Joined
Apr 1, 2018
Points
104
Location
Bristol
Model of Z
Z3 3.0 Z4 Coupe
Thanks for the detailed explanations and pictures guys , I’m not as enthusiastic about taking the dash apart so she may well have to live with it for now!
 
Top