Recently bought a headache!

[captain caveman]

Ok so picked up a 1997 Z3 last week needs a bit of tlc but ideal for a winter runabout.
Anyway the main problem is the alarm.
The owner told me about this but with holding the button down with the key on stopped the hazards flashing randomly but not any longer, Remote central locking is also not working.
So far ive found out one fault is the motion censor in the boot is a conman item to go Pete tong so looked in there and found its gone removed taken vanished!
The alarm siren has also been unplugged.
Any ideas around this problem? If i disconnected the alarm control unit will that cure the fault or immobilise the car?
Pm me if you rather no post on the forum.
Cheers guys

 

[captain caveman]

No ones had this problem before then?

 

[t-tony]

Do you have a key to turn off the "sounder" under the bonnet? What is the "motion sensor" in the boot. As far as I'm aware there is a switch incorporated on the boot lock assy.

Tony.

ps. @mrscalex

 

[GazHyde]

I'd imagine disconnecting the alarm will end up with immobilisation being triggered, they don't like leaving back doors in alarm systems.

Also worth unplugging the bonnet alarm switch. Another common point of failure, and can be left unplugged for diagnostics (or forever!)

EDIT: Realised it was Z3, not a Z4

 

[D R Oldfield]

Try unplugging the bonnet sensor on the front slam panel thus caused me no end of problems unplugged it and it's been perfect since

 

[captain caveman]

Thanks guys, The alarm is unplugged but the car still starts and drives as normal.
The rear motion sensor in the boot as already been removed, there no beep from the fob and it does not work the central locking either. I,l try unplugging the bonnet sensor tomorrow see if that makes any difference.

 

[captain caveman]

Just an update if anyone needs to know unplugging the alarm ecu make all problems go away.
No alarm no flashing lights and no immobilisation.
Starts and runs as normal and all done within 10 minuets.
Mods may want to delete or move this for obvious reasons.
This is for the Z3

 

[Jack Ratt]

Looks like you sorted it Captain

 

[mrscalex]

What do you call the alarm ECU? The alarm is just a dumb sounder with no control unit on all the Z3s I’ve ever seen. It’s just the mouth piece for the body control module if it detects an intrusion condition. Maybe the earliest cars are different?

The immobiliser on the cars I’ve seen is the EWS. If you remove that the car doesn’t start unless you reprogram the DME - the main computer.

 

[captain caveman]

There's a big control box hidden away, with 2 large block connectors coming from it. Quite well hidden but if you know where its a different mater, don't really want to go posting where it is pm me if you want to know.
Not taking about the alarm siren itself that was already unplugged