Trunk Lid Wiring Problem

[Geoff]

The trunk lid wiring harness on my 2000 Roadster was severed in half by the trunk lid hinge. I soldered the wires and covered in shrink tubing. After completing the work I noticed the following:

- Power door locks no longer work (worked before repairing wires)
- Side marker lights no longer work (worked before repairing wires)
- Brake light on trunk lid does not work (did not work before repairing wires)
- Trunk lid lock actuator does not work (did not work before repairing wires)

All of the fuses for these circuits are OK.

I noticed something strange as I was reconnecting the wires. As stated above, my wiring harness was cut in half. The half in the body of the car (near channel with rubber seal) has 1 solid brown wire. The half in the trunk lid has 2 solid brown wires. This is not reflected in any of the wiring diagrams I checked. When I connect either one of the brown wires in the trunk lid to brown wire near the trunk seal, the light inside the trunk turns on.

If anyone knows how to connect the brown wires, please let me know. I'd also appreciate your thoughts on why my side marker lights and power door locks no longer work. They worked before I re-connected the broken wires.

 

[Dino D]

It's a while since I did this but I recall something about not confusing the two browns.
I'm pretty certain you should have another brown wire coming out the the body side, perhaps it severed and got stuck out of sight so you need to pull the loom out a bit more?

 

[jonco]

Hi Geoff - maybe one for the auto electricians but from a basic point of view the brown is the common so that is why the light will work with either.

I assume you have no other wires `left over' and are just one brown short which sounds as if you have lost the common on the main circuit - suggest you peel back the loom covering a bit further back into the body and see if there are two browns there. You can pull the carpet back a bit to see it.

Edit - Dino beat me to it while I was typing

 

[Geoff]

Thanks. I'll take a look for another brown wire.

 

[Geoff]

I located and connected the second brown wire. Thanks to all for your help!

The brake light on the trunk lid works, but I still have problems:

- Automatic Stability Control warning light on dash illuminated (light was off before repairing wires)
- Power door locks no longer work (worked before repairing wires)
- Side marker lights no longer work (worked before repairing wires)
- Trunk lid lock actuator does not work (did not work before repairing wires)

Any ideas what might be wrong?

I have owned this car less than a year. Is the (2000) Z3 typically this problematic?

 

[Dickymint]

I don't think they are "problematic" but I think a lot of them have been neglected, mine is slowly getting back to how she should be after sorting the brakes and the idle and also dip in power when pulling off and the small rust spots under the bonnet are now sorted, not that there is not a small list left to do

 

[jonco]

I located and connected the second brown wire. Thanks to all for your help!

The brake light on the trunk lid works, but I still have problems:

- Automatic Stability Control warning light on dash illuminated (light was off before repairing wires)
- Power door locks no longer work (worked before repairing wires)
- Side marker lights no longer work (worked before repairing wires)
- Trunk lid lock actuator does not work (did not work before repairing wires)

Any ideas what might be wrong?.....

Looking at the wiring diagram the common goes back to a distribution system - I don't know what the effect would be if you have crossed these over @Aceman @Brian H @Brian4 may be the men to advise.

 

[Brian H]

I located and connected the second brown wire. Thanks to all for your help!

The brake light on the trunk lid works, but I still have problems:

- Automatic Stability Control warning light on dash illuminated (light was off before repairing wires)
- Power door locks no longer work (worked before repairing wires)
- Side marker lights no longer work (worked before repairing wires)
- Trunk lid lock actuator does not work (did not work before repairing wires)

Any ideas what might be wrong?

I have owned this car less than a year. Is the (2000) Z3 typically this problematic?

Not problematic Geoff the cars are getting on a bit now and need a little nurturing. I have attached a list below regarding the boot loom wires.

I Think the ASC light is a bit of an oddball and should not be affected at all by the boot loom (AKA The loom of Doom). I assume you have tried pressing the ASC switch? Take the car for a drive and see if the light extinguishes, Failing that I think you need to get a code reader and have a look to see what error has caused the ASC light to come on.

The power door locks, trunk actuator and side light problems sound like a fuse issue to me, I know you have checked these but failing a bad connection in the repair of the loom this is where I would look.

Boot Loom Wiring

As you can see below there are 9 wires in the boot loom, below the 9 wires are grouped with the function attached. The lock/unlock and switch position functions are controlled via the central ZKE module

The two wires below are part of a common loom that triggers the door actuator/lock.

• 1.5 BL/GR blue/grey - boot lock motor wire
• 1.5 WS white - boot lock motor wire

The three wires below are supply wires and lock position wires, the supply is fed from fuse 7 (5amp)

• 0.35 RT/GN red/green - boot lock switch - supply wire
• 0.5 WS/BL white/blue - boot lock switch - unlock wire
• 0.5 WS/GN/GE white/green/yellow - boot lock switch - lock wire

The two wires below are for the third brake light, the fuse for the third brake light is fuse F46 (15A) and controlled via the brake light switch.

• 0.5 BR brown - 3rd brake light - earth
• 0.75 BL/RT blue/red - 3rd brake light - supply Wire

The two wires below are for the boot interior light, this switch is located in the boot latch. The fuse for the boot light switch is F33 (10a).

• 0.5 BR/WS brown/white - boot light switch supply wire
• 0.5 BR brown - boot light switch - earth

 

[Geoff]

Brian, thanks for your help.

The wires are connected correctly. Fuses are good. I am going to have to live with the problems until I can have a dealer look at it.

 

[Geoff]

When I start the car, the ASC light turns on. If I press the ASC switch before starting the car, the light does not turn on. Any ideas what's happening?

The power door locks, trunk actuator and side lights still do not work.

 

[Geoff]

This car is frustrating.

The power door locks, trunk actuator, and side marker lights stopped working. And just last week the air conditioner stopped working. I've checked the fuses and wiring harness connections at the trunk lid. This is too much. At this point I'm not sure if I'll keep the car or sell it.

 

[jonco]

This car is frustrating..............

You have to remember Geoff - it is ~ 15 years old and lots of 15 year olds have frustrating problems that need sorting.

The central locking/alarm problem is quite common and can be very frustrating but it doesn't stop you driving a great car - hang on in there it will come good.

 

[Geoff]

Jonco, thanks for the reply.

I have a 38 year old Corvette that's never given me this many problems. It's also much easier to troubleshoot and service.

What's frustrating with my Z3 is the list of problems keeps growing. The car looks showroom new. On the other hand, I now understand why the previous owner sold it. I'm just going to drive the car the remainder of the summer with the ASC light illuminated (I forgot to mention this problem.). I'll likely sell it over the winter.

 

[Faheem]

I think I've finally fixed all my central locking issues. The boot locks correctly with the remote and boot light turns off when I close the boot or press the switch in. Unfortunately I've cut a bit of the wire too short - it's a brown wire that runs from the boot lid into the boot. I need to buy some additional wire but don't know what the correct spec is. Once I get the wire I can crimp in and connect it to the existing wiring to complete the circuit. Any ideas?

 

[t-tony]

Visit your friendly breaker Faheem and chop a bit out of a car.

Tony.

 

[jonco]

I think I've finally fixed all my central locking issues. The boot locks correctly with the remote and boot light turns off when I close the boot or press the switch in. Unfortunately I've cut a bit of the wire too short - it's a brown wire that runs from the boot lid into the boot. I need to buy some additional wire but don't know what the correct spec is. Once I get the wire I can crimp in and connect it to the existing wiring to complete the circuit. Any ideas?

Congrats on the fix - the brown wires are both 0.5 they are the earth wires for the boot lock and third brake light - you can use bigger.

 

[Faheem]

Thank you both!

 

[topcat59]

Not problematic Geoff the cars are getting on a bit now and need a little nurturing. I have attached a list below regarding the boot loom wires.

I Think the ASC light is a bit of an oddball and should not be affected at all by the boot loom (AKA The loom of Doom). I assume you have tried pressing the ASC switch? Take the car for a drive and see if the light extinguishes, Failing that I think you need to get a code reader and have a look to see what error has caused the ASC light to come on.

The power door locks, trunk actuator and side light problems sound like a fuse issue to me, I know you have checked these but failing a bad connection in the repair of the loom this is where I would look.

Boot Loom Wiring

As you can see below there are 9 wires in the boot loom, below the 9 wires are grouped with the function attached. The lock/unlock and switch position functions are controlled via the central ZKE module

The two wires below are part of a common loom that triggers the door actuator/lock.

• 1.5 BL/GR blue/grey - boot lock motor wire
• 1.5 WS white - boot lock motor wire

The three wires below are supply wires and lock position wires, the supply is fed from fuse 7 (5amp)

• 0.35 RT/GN red/green - boot lock switch - supply wire
• 0.5 WS/BL white/blue - boot lock switch - unlock wire
• 0.5 WS/GN/GE white/green/yellow - boot lock switch - lock wire

The two wires below are for the third brake light, the fuse for the third brake light is fuse F46 (15A) and controlled via the brake light switch.

• 0.5 BR brown - 3rd brake light - earth
• 0.75 BL/RT blue/red - 3rd brake light - supply Wire

The two wires below are for the boot interior light, this switch is located in the boot latch. The fuse for the boot light switch is F33 (10a).

• 0.5 BR/WS brown/white - boot light switch supply wire
• 0.5 BR brown - boot light switch - earth

Brian,

quick question - thanks for the wiring sheet.

my central locks were not working - the 25A fuse was blown. Replaced the fuse, put the key in and turned the lock - fuse blown.

given things i read on this site - i suspected an issue in the boot, so i checked the wiring , after that i tried to eliminate components -

so i checked the actual latch - it has a plug in it with a blue/ grey and a white - when i disconnect and replace the fuse, leaving that unpliged all works -

this car has had some rear damage repaired by a previous owner and i am thinking somehow this plug goes to the actuator and not the latch itself - could that be the issue?

thanks!
Tom

 

[gookah]

heated door mirror wiring?

 

[Faheem]

Brian,

quick question - thanks for the wiring sheet.

my central locks were not working - the 25A fuse was blown. Replaced the fuse, put the key in and turned the lock - fuse blown.

given things i read on this site - i suspected an issue in the boot, so i checked the wiring , after that i tried to eliminate components -

so i checked the actual latch - it has a plug in it with a blue/ grey and a white - when i disconnect and replace the fuse, leaving that unpliged all works -

this car has had some rear damage repaired by a previous owner and i am thinking somehow this plug goes to the actuator and not the latch itself - could that be the issue?

thanks!
Tom

Yes that could be the issue. That's exactly the issue that I had. And it happens simply because the connectors appear identical and therefore can plug into either the actuator or the wiring for the microswitch that controls the boot light (near the latch). Try and swap the connectors over to see if this resolves the issue.