Solving various electrical issues

donutholer

Regular Member
Joined
Jun 18, 2025
Points
18
Hi all, I would absolutely love some help with my current issue with my beloved z3

Out of nowhere, (cleaning the trunk was the last thing I did) the electrical systems started going haywire:

car when turned on went in anti theft/alarm mode (pulled alarm fuses in order to start the car)

window that previously worked now doesn’t work,

the tail reverse light that worked now doesn’t work, and the other side that didn’t work now works (put new bulb in)

entire dash dials don’t work (all show lowest for rpm, speed, fuel, coolant temp)

I know the sensors are working, through the OBD I can see the coolant temp and also RPM.

anyone have tips or idea how I can start to sort these electrical gremlins out? the window isn’t the worse thing in the world but I really want my dash working. Computer seems to turn on (lights on the dash for ABS and also parking brake)
 

Ianmc

Zorg Guru (IV)
British Zeds
The M44 Massive
Joined
Oct 12, 2014
Points
165
Location
New Forest
Model of Z
Z3 (M44)
My first check would be "the loom of doom", especially as you have been working in the boot. :thumbsup:
 

NZ00Z3

Zorg Guru (IV)
Supporter
New Zealand Zeds
Joined
Dec 9, 2014
Points
158
Location
Timaru, New Zealand
Model of Z
3.0L, 2.8L, 2.0L Z3 Roadsters
Depending on the model of Z3, this sort of broken wire at the positive terminal can cause all sort of problems.

1755460292298.png
 

donutholer

Regular Member
Joined
Jun 18, 2025
Points
18
My first check would be "the loom of doom", especially as you have been working in the boot. :thumbsup:
I checked already, don’t think I saw any bent cables but I’ll probably have to cut the wrap more to check for sure. Is there a particular spot that’s the most common or should I just remove the whole black casing
 

Oddly Godly

Zorg Guru (III)
Supporter
British Zeds
Joined
May 17, 2019
Points
135
Location
dunstable
Model of Z
z3 2.8
Under the carpet infront of the rear left light is a well that can fill with water. This covers the tilt sensor and makes the alarm go off. Water often gets in from the antenna grommet. It can build up slowly as it is unseen. If it is full of water use a spong to try and remove the water
 

donutholer

Regular Member
Joined
Jun 18, 2025
Points
18
Under the carpet infront of the rear left light is a well that can fill with water. This covers the tilt sensor and makes the alarm go off. Water often gets in from the antenna grommet. It can build up slowly as it is unseen. If it is full of water use a spong to try and remove the water
No water, car has been in the garage for a month, and during this time the electrical issues began occurring
 
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