E86 Coupe Alarm Fault

[Jay-Z4]

My alarm is going off at random times when the car is locked. Sometimes straight after I lock it, sometimes hours after. The only time I can stop it going off is turning the alarm off.

Other than going to a main dealer, any suggestions?

 

[Taz]

bonnet switch is a known fault - no coupe specific though

 

[markplant]

+1 for bonnet switch

 

[Scooba_Steve]

£10 part and 5 mins to swap - first item to try. Unplugging it will also work to fault find or if you're feeling particularly tight.

 

[Rorybeanbutler]

I unplugged my bonnet switch over a year ago and have never looked back.

 

[Jay-Z4]

I've unplugged the bonnet switch but the alarm still goes off at random times.

I'm guessing the fault is going to be a costly one to get fixed

Are there any other common faults like the bonnet switch or do I need to get it properly diagnosed by a main dealer?

 

[Taz]

Intermittent faults can be a nightmare to find urghhhhhhhhhhh

 

[Jay-Z4]

Recently had to replace the battery on my Zed and since then the alarm had been working fine. I thought the drained battery was causing an electrical fault with the alarm, however today the alarm has randomly gone off again

Going to have to give the bonnet switch replacement a try. Will any BMW bonnet switch fit an E86 or does it need to be a particular one? Surprised how cheap they were (£10 off fleabay)

 

[Rorybeanbutler]

Recently had to replace the battery on my Zed and since then the alarm had been working fine. I thought the drained battery was causing an electrical fault with the alarm, however today the alarm has randomly gone off again

Going to have to give the bonnet switch replacement a try. Will any BMW bonnet switch fit an E86 or does it need to be a particular one? Surprised how cheap they were (£10 off fleabay)

Just unplug it. Did it when I bought the car and never looked back.

 

[Jay-Z4]

Recently had to replace the battery on my Zed and since then the alarm had been working fine. I thought the drained battery was causing an electrical fault with the alarm, however today the alarm has randomly gone off again

Going to have to give the bonnet switch replacement a try. Will any BMW bonnet switch fit an E86 or does it need to be a particular one? Surprised how cheap they were (£10 off fleabay)

Just unplug it. Did it when I bought the car and never looked back.

I've unplugged it before but that didn't fix the problem

 

[Scooba_Steve]

Then replacing it won't either.

Unplugging disables it - you may have had issues with the battery that affected it. Unplug and try again as you have changed a variable. If that does indeed solve the problem you can replace if you still want a bonnet alarm, or leave unplugged, the choice is yours.