Thread: Horn beeps when locking

One of the door switches or bonnet switch or wiring to them is the problem, first unplug the bonnet switch and try so, if it stops there it is, if you still get the misslock with unplugged bonnet switch leave the driver's window open lock with key and open the door through the window, if the alarm goes off the problem is in one of the other 3 doors or tail door cos these are all together on the same input to BCU so you'll have to make measurements with multimeter to see which one is closed circuit, if the alarm doesnt go out this way the problem is at the driver's door

keep the fob in hand to disarm the alarm if it goes off, you have to lock with key to not trigger the volumetric alarm when you reach to the interior handle, the switches are part of the actuators and they all must be open with closed doors, when a door is opened the switch closes to earth so as long as the BCU gets an earth input from one of the switches it triggers the alarm/misslock warning if you see what i mean

Check the switch mount under the bonnet it may be bent over and if so the switch will not contact the bonnet correctly

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Originally Posted by sierrafery

One of the door switches or bonnet switch or wiring to them is the problem, first unplug the bonnet switch and try so, if it stops there it is, if you still get the misslock with unplugged bonnet switch leave the driver's window open lock with key and open the door through the window, if the alarm goes off the problem is in one of the other 3 doors or tail door cos these are all together on the same input to BCU so you'll have to make measurements with multimeter to see which one is closed circuit, if the alarm doesnt go out this way the problem is at the driver's door

keep the fob in hand to disarm the alarm if it goes off, you have to lock with key to not trigger the volumetric alarm when you reach to the interior handle, the switches are part of the actuators and they all must be open with closed doors, when a door is opened the switch closes to earth so as long as the BCU gets an earth input from one of the switches it triggers the alarm/misslock warning if you see what i mean

Alright the problem is now down too one of the three doors or the boot. What is the best way to go about testing for a circuit. In other words where should I be sticking the multimeter exactly I have a feeling it's the passenger door or lhr as I had a sticky situation in some salt water the other day on that side. Could it be a simple case of a wire out or a corodded wire ?

It's not about wire out or corroded cos then it should be open circuit to earth and no misslock, in your case on one of those switch circuits it's a closed to earth input to BCU(they are all joined) the simplest but a bit laborious is to remove the door cards one by one and unplug each actuator at a time, close doors then lock with fob... when you dont get the misslock after unplugging one there it is the problem(maybe you are lucky to find it from first attempt)...if the misslock will persist with all disconnected then it's a short to earth somewhere and we'll speak then cos it becomes complicated

Originally Posted by sierrafery

It's not about wire out or corroded cos then it should be open circuit to earth and no misslock, in your case on one of those switch circuits it's a closed to earth input to BCU(they are all joined) the simplest but a bit laborious is to remove the door cards one by one and unplug each actuator at a time, close doors then lock with fob... when you dont get the misslock after unplugging one there it is the problem(maybe you are lucky to find it from first attempt)...if the misslock will persist with all disconnected then it's a short to earth somewhere and we'll speak then cos it becomes complicated

So is it the actuator that would cause the miss lock in the end of the day or is there an easier fix. Im still a little bit confused.

It's or the actuator(the door switch is part of it) or a wiring issue as the BCU gets an earth input on the port which is for the passengers and tail door surveillance(re-read all my statements cos IMO it should be relevant enough)

Originally Posted by sierrafery

It's or the actuator(the door switch is part of it) or a wiring issue as the BCU gets an earth input on the port which is for the passengers and tail door surveillance(re-read all my statements cos IMO it should be relevant enough)

I will have a look tomorrow a little loud right now for the neighbors.. I know my driver door actuator is buggered as it doesn't unlock I actually have one being shipped to me as we speak so was planning an install soon. But now this problem has occurred.

I will try unplug the actuators left side first as I feel it potentially may be caused by some ocean water on the left hand side of the car. Is there just a direct switch to pull the actuator out or do I have to do the full uninstall (torx screwdrivers) ect..

The water may of shorted something as well but will run the tests. (possibly in those 3 holes at the base of the passenger door)

I read elsewhere that potentially there is a sequence of which unlocking and locking through a mixture of the fob and door lock the mislock can be revesed?Can anyone confirm this ?