MgF Bonnet Switch Wiring - FIXED

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NapalmNick
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MgF Bonnet Switch Wiring - FIXED

Post by NapalmNick » Sat Aug 19, 2017 6:46 pm

Hi all I have searched the forum but seems my problem is an oddity?

The bonnet switch wire on my vvc does not exist lol. By that i mean the switch is there and i have cleaned and tested it as functional but the wire that connects to it for the bonnet light and alarm is not connected and i can't see a loose one hanging about anywhere in the vicinity.

I can get the light working running a rabbit wire from the switch onto the right side switch wiring (neg return) but ideally i would like to regain both light and alarm function with the proper connector.

I guess it might of been chopped off in frustration by someone having an alarm issue previously but i cant see any mad axeman cuts. :o

So my question is can someone have a look at theirs sometime and let me know where the switch wire is coming from - if I had to guess it would be the loom near to it which would connect to the nearside loom switch wiring. Or did Rover forget it on some cars lol.

Thanks in advance,
Nick
Last edited by NapalmNick on Fri Sep 08, 2017 1:56 pm, edited 1 time in total.

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Re: MgF Bonnet Switch Wiring

Post by NapalmNick » Tue Sep 05, 2017 12:28 pm

Further to this the boot alarm isn't working either (the light is) so I am guessing it has caused problems in the past. But the lack of wiring is confusing. Surely if it was causing problems you would disconnect it not remove wires?
Anyhoo looks like I am on my own with this one. :sf: ;)

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Re: MgF Bonnet Switch Wiring

Post by daz » Tue Sep 05, 2017 1:49 pm

what do you mean the boot alarm isn't working? The alarm won't sound if you open the boot with the key. IIRC the wire for the switch comes from next to the wing. I can't check at the moment as I haven't got room to open my bonnet.

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Re: MgF Bonnet Switch Wiring

Post by NapalmNick » Wed Sep 06, 2017 10:20 am

Thanks Daz

I have tried to activate the boot alarm by operating the switch manually i had read that using the key wont make it alarm so tried manually. I assume of course it is triggered by the same switch as the light like the front (I will have to double check the wiring diagram again).
The alarm works generally (on the doors and by motion) and the bonnet switch has no wires attached at all.

Yes it makes sense the wiring would come from the loom near the switch. Just can't see any cut ends or new looking electrical tape.
I will probably rabbit run to get the courtesy light working for the sake of 'everything works' but yeh no rush it is a minor annoyance on the list of imperfections hehe.

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Re: MgF Bonnet Switch Wiring

Post by daz » Wed Sep 06, 2017 11:29 am

The switch for the boot light is built into the lock. How are you testing the alarm for the boot?

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Re: MgF Bonnet Switch Wiring

Post by NapalmNick » Wed Sep 06, 2017 12:58 pm

Initially i opened the boot with the key and shut the lock with a screwdriver to the point the light went out (thinking this would fool the alarm to beleive the boot was shut). Then locked the car and waited for the alarm to set completely.
Then i released the boot catch and light come on but no alarm.

Secondly i ran the alarm test procedure and the doors and motuon sensor tested correct (light flashed for a secind in each case). Using the spare key i opened the boot but no dashboard flash. To me that is confirmation or am i wrong?

Obviously no point testing the bonnet as there are no wires on the switch. Hoho.

So the boot may be crimped wires or disconnected wires or even cut off and removed wires like the bonnet. I have yet to delve into this further. It is just something i noticed while trying to figure the bonnet problem.

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Re: MgF Bonnet Switch Wiring

Post by NapalmNick » Wed Sep 06, 2017 12:59 pm

:roll: Excuse the fat fingers small phone spelling

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Re: MgF Bonnet Switch Wiring

Post by daz » Wed Sep 06, 2017 1:06 pm

when you opened the boot by releasing the boot catch this fooled the alarm into thinking the key was used.

Opening the boot won't make the light flash because you're using the key, I'd imagine it's all working correctly.

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Re: MgF Bonnet Switch Wiring

Post by NapalmNick » Wed Sep 06, 2017 2:09 pm

Ah yes I can understand that. Maybe the only true test will be to pry the boot open with a crowbar! :twisted:

I can see my manual test is not valid. I just rechecked the wiring diagram too but it doesn't really explain how using a key overcomes the alarm. If the catch is the only switch then how does it sense the boot has been forcibly opened? I probably need to 'boff up' on this subject and not waste your time.

My interpretation of the alarm test procedure is that the boot will cause a 1 second flash even if opened with the key.
Opening either door, the bonnet or the boot lid, or operating the driver’s doorsill button, will cause the alarm LED to illuminate for approximately one second. If the LED does not illuminate, there is a system fault.
But that makes little sense as all the other tests are detecting the alarm being triggered...I assume.

Hopefully you are right and all is well boot wise. So just need to find that bonnet switch wire.

Appreciate you taking the time to reply Daz.

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Re: MgF Bonnet Switch Wiring

Post by John SS » Wed Sep 06, 2017 4:04 pm

Hopefully this will answer your original question. The wire is black with purple trace.
image.jpeg

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Re: MgF Bonnet Switch Wiring

Post by NapalmNick » Wed Sep 06, 2017 4:43 pm

Ahhhh wonderful pic and thx for the colour ident.

Will be able to hunt that down hopefully. I will let you know.

Thanks guys very much appreciated. :thumbsu:

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Re: MgF Bonnet Switch Wiring

Post by talkingcars » Wed Sep 06, 2017 10:13 pm

The boot isn't connect to the alarm so that you can access the boot without unlocking the car.
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Re: MgF Bonnet Switch Wiring

Post by Roverlike » Thu Sep 07, 2017 6:17 am

NapalmNick wrote:Ah yes I can understand that. Maybe the only true test will be to pry the boot open with a crowbar! :twisted:

I can see my manual test is not valid. I just rechecked the wiring diagram too but it doesn't really explain how using a key overcomes the alarm. If the catch is the only switch then how does it sense the boot has been forcibly opened? I probably need to 'boff up' on this subject and not waste your time.

My interpretation of the alarm test procedure is that the boot will cause a 1 second flash even if opened with the key.
Opening either door, the bonnet or the boot lid, or operating the driver’s doorsill button, will cause the alarm LED to illuminate for approximately one second. If the LED does not illuminate, there is a system fault.
But that makes little sense as all the other tests are detecting the alarm being triggered...I assume.

Hopefully you are right and all is well boot wise. So just need to find that bonnet switch wire.

Appreciate you taking the time to reply Daz.
What you write here and expect for led to illuminate for one second is true IF YOU ARE IN ALARM SELF TEST MODE.

There are two switches in the boot: Boot switch which would operate boot light and boot lock switch, which would give info if boot is opened by key. Both of these switches are connected to alarm box.

The best test would be to anter into alarm self test mode and check your boot switch alarm function. Here you have how to do that: https://www.the-t-bar.com/forum/21-davi ... ow-to-test

This black wire with purple trace is singlemwire connected with one end to bonnet switch and the other end goes to two places: alarm box and bonnet lamp. This switch provide earth connection to alarm when opened and earth connection to lamp when opened. Lamp gets power from fuse box.

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Re: MgF Bonnet Switch Wiring

Post by NapalmNick » Thu Sep 07, 2017 9:54 am

Yikes the topic has come alive and is Frankensteins Monster reincarnate. :o lol.
talkingcars wrote:The boot isn't connect to the alarm so that you can access the boot without unlocking the car.
I can see on the wiring diagram links from the boot switch to the alarm ecu. The boot not being alarmed so thieves can steal my luggage doesn't ring right.
Roverlike wrote:What you write here and expect for led to illuminate for one second is true IF YOU ARE IN ALARM SELF TEST MODE.
I was
me wrote:Secondly i ran the alarm test procedure and the doors and motion sensor tested correct (light flashed for a second in each case). Using the spare key i opened the boot but no dashboard flash.
No flash so an error it seems. The plot thickens and goes back to me thinking a previous owner has disconnected the bonnet/boot alarms for some reason.

2 switches for the boot? Yes that makes sense i just cant see two on the wiring dia anywhere but i also read this before in another thread so i will investigate in that direction too.

EDIT: Roverlike your link to the test procedure says "Boot Switch" and "Boot Cylinder lock" as two tests so implies you are correct! First time i have seen two references for the boot area.

Good info guys thank you. Remember i havent really looked into the boot wiring yet just hunting the bonnet switch return earth lead. Pesky varmint. :D Will keep you and Mary Shelley updated.

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Re: MgF Bonnet Switch Wiring

Post by Roverlike » Thu Sep 07, 2017 5:07 pm

I am sorry, must slipped from my reading that you were in test mode. However, if no blink on the dash, would mean that switch does not operate correctly?

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Re: MgF Bonnet Switch Wiring

Post by NapalmNick » Thu Sep 07, 2017 5:31 pm

Yep, switch, broken wire by the hinge, disconnected, cut off :rant:, or the alarm ecu itself.

We will get there!
Only had a few minutes time to search again for the bonnet wires today but no luck. I will carefully open up the loom to hunt for that wire next.....

Thanks guys.

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Re: MgF Bonnet Switch Wiring

Post by talkingcars » Fri Sep 08, 2017 12:26 am

NapalmNick wrote:Yikes the topic has come alive and is Frankensteins Monster reincarnate. :o lol.
talkingcars wrote:The boot isn't connect to the alarm so that you can access the boot without unlocking the car.
I can see on the wiring diagram links from the boot switch to the alarm ecu. The boot not being alarmed so thieves can steal my luggage doesn't ring right.
Oh, sorry, I bow down to your superior knowledge.

I always thought the ECU that controlled the alarm also controlled the interior lighting but perhaps I know nothing.

And maybe all the people who have locked their keys in the boot have been mistaken.................
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Re: MgF Bonnet Switch Wiring

Post by NapalmNick » Fri Sep 08, 2017 9:56 am

I doubt a noob to the car and forum could possibly have any superior knowledge over a chap as exprienced as you so sorry if you took my reply as dismissive rather than just questionative (is that a word?). It just didnt sound right. Like i said.

I see your reasoning now you explain it - the ECU controlling the courtesy lights exterior and interior too. Which is interesting indeed.

The only knowledge i can base my questions on is what i read like page.5 of the Owners Manual:
FEATURES OF THE ALARM SYSTEM

Perimeter Protection: This part of the alarm system protects the doors, bonnet and boot lid - the alarm will sound if any one of these apertures is opened improperly

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Re: MgF Bonnet Switch Wiring

Post by NapalmNick » Fri Sep 08, 2017 12:21 pm

So I carefully opened up the loom closest to the bonnet switch and found a Black with Purple trace but no cut ends and it seems to happily run down to the ABS area :( The grommet is removed and I have unwrapped the other direction too but nothing to note the wires seem unmolested. All electricians are probably grimacing but don't worry I is one (though not automotive).
Of note my through-bonnet layout is different to the picture John SS kindly posted (mines a 2000 VVC) hopefully you can see from the pic below:
MG Bonnet OS Grommets.JPG
The main thing is that on Johns the wire doesn't seem to be entering the main loom but goes through another grommet. The black/purple wire in my pic is the one slightly on its own on the left . I reckon this main loom wire is not destined to be bonnet switch related I reckon there should be another one (guessing). I removed the courtesy light on the other side and it has a black/purp going to it. You can see the switch but nothing going to it.

Hmm so now I have to decide if I want to rummage around more in this old electrics and risk disturbing something or just rabbit run to get the courtesy light working but always know the bonnet alarm isn't connected properly :thumbsd: .

Any suggestions?

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Re: MgF Bonnet Switch Wiring

Post by NapalmNick » Fri Sep 08, 2017 12:37 pm

PS: just found the right diagram showing MGF boot switch and Boot key switch thanks Roverlike! also shows Black Purple as correct John.

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