MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - Alarm - PANIC, urgent, help....eek

Don't shout...

There are so many alarm archives and I am sifting through them.

In the meantime, how do I lock my poor MGF without setting the alarm?

I could do with this kinda quickly..
Neil H

Just use the key Neil.

Sam
Sam Murray

Tried that... that sets the alarm too.
Neil H

I don't think you can (except from using the door buttons. The key activates the alarm but not the volumetric sensor. You could just take out the alarm fuse, but you would have to replace it and push the blipper 4 times when you want to start the car.
Will Munns

Struth..

I can't work out the cause.. just yet.
The key still sets my alarm off.

I have no phones, micorwaves etc.. rule that one out.

I have just driven to France and back, so the battery should be in excellent health.

I haven't got time to get it into a garage before I have to park it in public for a whole day.

If I take the fuse out of the horn will I still have big battery drain?
Neil H

Probably a faulty door lock mechanism Neil. The lock and the alarm are inter connected.
D Jamieson

How about unlocking the car with the key and then using the Emergency Key Activation Code. The code is input by using the key in the driver's door. The sequence is explained in the operator's manual.

I believe that doing this will deactivate the immobiliser and alarm until you once again use the blipper.

This should work for older Fs and any Fs which don't have the transducer built into the key.

Bruce
Bruce Caldwell

It will be the door lock/bonnet switch/boot switch wireing on the way out (check interior lights) Pulling the horn fuse will lead to power drain, You want to pull the alarmn ECU fuse from the uner bonnet fusebox (fuse 3?)
Will Munns

Okay, how about the idea Bruce has of disabling the sytem until I sort it?

I have the card..

I think I have read something before about the number being wrong on earlier models.. which numbers do I increment?
Neil H

I don't think this does the alarm, mearly the immobilizer.
Will Munns

You could pull the boot lamp and connect the Purple wire with a red stripe to ground. Then the ECU would assume the boot was open, the fob would operate the door locks and the imobilizer.
Will Munns

Now I like that bit of thinking Will..!!

I have disabled the immobilser and the car is sat in the car park at work.. locked.., and I am waiting for it to go off again.

At lunch I think I'll buy some wire and clip and do what you just suggested..
Neil H

You are right Will. My idea just decativates the immobiliser. Just read the hand book.

You could just pull the connectors on the horns. Stops the noise and reduces the current drain.

Bruce
Bruce Caldwell

But if I pull the connectors on the horns, then the indicators will still flash all the time..

.. the alarm still hasn't gone off yet....
Neil H

If your indicators are flashing when the alarm goes off then I suggest a trip to the MG dealer for a software patch to stop it, this is a potential security hole, patched silently as a routine upgrade (and only on the TF)
Will Munns

Oh! I was just assuming they did! I haven't really looked!!!!

Neil H

In what way is it a security hole (presumably it's a symptom of something else)? I'd always thought it odd that they don't flash.

Tim.
Tim Jenner

>You could pull the boot lamp and connect the Purple wire with a red stripe to ground. Then the ECU would assume the boot was open, the fob would operate the door locks and the imobilizer.

Will; I looked at my boot lamp at lunchtime which has always hung out of its hole (one of the tabs is snapped off the light fitting).
The light does seem a bit tempremental if I wiggle the purple/red wire.
How does this all work and link the boot then?
Could this be the cause?
Neil H

>In what way is it a security hole
If it's all the same to you I'd rather not discuss it here, suffice to say, if they flash when the alarm goes off then a trip to the dealer is in order.

>How does this all work and link the boot then?
The bootlight is connected to a fuse on one side and the switch on the other(purple/red), the switch pulls the purple wire to ground when the boot is open, thus the light lights up. When the boot is not open the voltage passes thru the lamp and by observing the voltage on the wire the ECU can tell if the boot is open.*

>Could this be the cause?
If the purple/red wire rubs on the body and shorts out then YES!

Will

*analogy
The light acts like a dripping tap on a hose, with the switch to ground the water passes thru the tap, on the feed side of the system the pipe is at high pressure (voltage), on the hose side there is very little pressure(voltage). This is like the switch being on. Now stop the flow of water (electrisity) by blocking the hose with your thumb (opening the switch). Now the pressure in the hose builds up untill it reaches the pressure of the water in the pipe upstream of the tap. so looking at the pressure in the hose you acn tell your thum is blocking it.
Will Munns


There is also a sensor on the key switch which disrms the alarm if the boot is opened with the key whilst the alarm is on.
Will Munns

I see. I really am learning today.. Thanks Will.
So, my wire doesn't look worn, but cold be since the light seems to be flickery if I move the wire around.

Short term fix, connect the red/pruple wire to earth - this will not drain the battery and will convince the ECU that the boot is open, whilst maintaining the immobiliser.

Long term fix, find the fault with the wire, or visit the dealership.

Correct?

-- I am presumme this security conversation with Tim is basically that the flashing indicators is a sign of the security risk, and not that flashing indicators on all cars means that their vunerable.

Neil H

Neil,
If the blade the spade connect onto is rubbing against the body then it might be that, otherwise (on that circuit) there are known problems with where the wire threads around the hinge (so have a look there for bare wires).
However if the interior lights come on when the alarm goes off then the fault is in a door lock.

>connect the red/pruple wire to earth - this will not
>drain the battery
as long as you also disconnect the light ;-)

>and will convince the ECU that the boot is open
correct.

Will Munns

Ah.. major clue there then.. The interior lights do NOT go on when the alarm goes off..

The boot light wires look to be in good condition. The bulb holding mech though seems a bit corroded.., but I don't think the logic works that way round (no light when boot is open shouldn't matter).

I will wait til I get home and look under the bonnet too..

Bit worried that I had an over-packed boot last week and I've forced something horrible.

Thanks for all the help Will.. - I owe you a beer!
Neil H

> there are known problems with where the wire threads around the hinge (so have a look there for bare wires).

Neil, keep an eye on that location. It's prone to fail, just below the cable tie at the hinge.

>You could pull the boot lamp and connect the Purple wire with a red stripe to ground. Then the ECU would assume the boot was open, the fob would operate the door locks and the imobilizer.

@ Will, good idea mate :)
Dieter K.

This thread was discussed on 01/10/2003

MG MGF Technical index

This thread is from the archives. Join the live MG MGF Technical BBS now