Ticking noise from under the bonnet when parked and locked.

[edwardmk]

Well I got a chance to try again after work. Connected the V8 battery to pin 9 and the chassis. Immediately the alarm went off, so I'm assuming pin 9 has no relay and goes direct to the battery on my car. I left the battery connected with the ctek charger in parallel and ignored the alarm for a few minutes. I got close to the car and pressed the fob four times. I noted the red light on the fob was working. I repeated this several times but to no avail. Car remains firmly locked up. So at the weekend it looks like I'll be mangling my hands trying to get to the bonnet cable via the wing. I'm left wondering whether my changing the fob battery might have sabotaged Jon's solution.

[SD1too]

Originally Posted by edwardmk

I'm left wondering whether my changing the fob battery might have sabotaged Jon's solution.

No it won't have done Martin. The fob battery powers only its circuit board which sends an RF signal to the receiver in the car. Since the car's battery is completely discharged, the receiver is most likely unable to function, hence the doors remain locked.

The alarm is sounding because the battery voltage is so low that the electronics think that it's been disconnected by a thief (the BBUS alarm sounder has its own independent battery).

Simon

[Rick-sta]

Just a thought, when you get a bit if power try using the key in the drivers door lock and hold it in the unlock position and see if the windows open. Id enabled the lazy venting option on it. Not sure if that will still work even though the drivers door won't open with the key.

[edwardmk]

Originally Posted by Rick-sta

Just a thought, when you get a bit if power try using the key in the drivers door lock and hold it in the unlock position and see if the windows open. Id enabled the lazy venting option on it. Not sure if that will still work even though the drivers door won't open with the key.

That sounds interesting. It's worth a shot before taking the wheel off. I'll try that tonight weather permitting.

[SD1too]

Originally Posted by edwardmk

It's worth a shot before taking the wheel off.

Rick's suggestion isn't going to work with a flat battery Martin. Your only option is to get the bonnet open to charge the battery and the sooner you do that, the better.

Simon

[edwardmk]

Originally Posted by SD1too

No it won't have done Martin. The fob battery powers only its circuit board which sends an RF signal to the receiver in the car. Since the car's battery is completely discharged, the receiver is most likely unable to function, hence the doors remain locked.

The alarm is sounding because the battery voltage is so low that the electronics think that it's been disconnected by a thief (the BBUS alarm sounder has its own independent battery).

Simon

Thanks for that information Simon. Just wondering, if the electronics detect a low voltage and that sets off the BBUS, why doesn't the BBUS sound every time the car battery drops below a certain voltage as it goes flat while being unused?
Also I recollect disconnecting the battery myself a few times to be safe while working on the car, and the alarm stayed silent. I'm guessing this was because the car wasn't locked. However, I locked the car on Thursday, so in theory, if the car battery ran down, should it not have fired up the BBUS at some point?
By connecting 12.8v to pin 9, that instantly fires up the BBUS which is actually increasing the voltage.
At least I'm very grateful the MG BBUS turns off when I disconnect pin 9. I have an Astra turbo from which I removed the BBUS a few years ago when it kept randomly annoying the neighbours. I had ear defenders on, and put it in a bucket with foam all over it in a cupboard in the garage. It sounded for two days before giving up. With hindsight I should have used a sledgehammer on it but at the time I was thinking I might try to fix it.

[Rick-sta]

Originally Posted by SD1too

Rick's suggestion isn't going to work with a flat battery Martin. Your only option is to get the bonnet open to charge the battery and the sooner you do that, the better.

Simon

ah that's a shame.

[COLVERT]

There's one last thing that just came to me.---You have a tow hitch fitted.--It might be wired direct into the car's wiring. ( Rear light clusters. ) However it is advised to fit a relay so as not to overload the cars wiring or upset the function of the ECU. If it has a relay then this is normally fitted into the boot of the car.---There is a way of getting into the boot without doing any damage. The relay, if there is one, will have a positive live wire directly to the battery positive terminal.

I can't remember on the forum where the information is on how to get into the boot but I guess somebody will read my post and know how to do this.--

[chris75]

Originally Posted by edwardmk

I have an Astra turbo from which I removed the BBUS a few years ago when it kept randomly annoying the neighbours. I had ear defenders on, and put it in a bucket with foam all over it in a cupboard in the garage. It sounded for two days before giving up. With hindsight I should have used a sledgehammer on it but at the time I was thinking I might try to fix it.

I've been there ! I had an MG ZR with a BBUS which kept going off at random times and I also ended up burying it in a cupboard after removing it until it died . I then disconnected the internal batteries to prevent them recharging and refitted it . No more problems ever again , and the rest of the alarm system carried on working fine I concluded that the problem was with the BBUS device , but decided I could live without it !

[edwardmk]

Originally Posted by chris75

I've been there ! I had an MG ZR with a BBUS which kept going off at random times and I also ended up burying it in a cupboard after removing it until it died . I then disconnected the internal batteries to prevent them recharging and refitted it . No more problems ever again , and the rest of the alarm system carried on working fine I concluded that the problem was with the BBUS device , but decided I could live without it !

I made the same decision I could live without it, but I left mine off the car. I didn't think about it affecting the rest of the electronics but I seem to have got away with it. Very happy without the alarm. Has a car burglar alarm ever done anything except annoy the owner ?