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Car Alarm Becoming Annoying

scam75

scam75

Well-known member
Hi All

My car has what I assume was a factory or dealer fit alarm/immobiliser. Single button key fob, nothing to insert with a micro chip. One press locks doors and arms immobiliser and is accompanied by a single indicator flash. Next press opens doors, disarms immobiliser and has 2 indicator flashes. Not sure of the make, but have noticed the starter will spin on key turn with alarm on, but it won't start so fuel/ignition must be cut off. Anyway hope someone can ID it from that!

So long story short, not really caused any problems over the years but has had a tendency from time to time to go off once, soon after parking hot, and then it calms down. It likes to do it at the golf course as I am about to tee off! Any time it does this it only happens once. Last few days, possibly heat related (air temp, been unusually hot in Scotland), it has started to sometimes go off for a 2nd or 3rd time. If the engine is cool it never goes off, ever. So can lie for a week with no issues. I would assume something is/has become over sensitive but not sure where or what. The siren is located in the bulk head, next to outdoor temp sensor, and is extremely loud and doesn't seem to have been worn out even slightly in 29 years!

Any help/ideas greatly appreciated as I feel she may be close to being attacked with a golf club soon (not by me of course!) if these hissy fits persist!

Cheers

Stuart
 
Stuart,

Old alarms are very often trouble. They are not usually made from the best components but (more significantly) often very badly fitted. If yours was fitted from new (or soon after new) then you're doing well.

The easy option is to disconnect the siren. Some wire snippers are a nice easy way of doing this and they will stop it from shrieking and will allow it to continue as an immobiliser, but this isn't solving the problem it is merely masking the symptoms. The proper answer is to find someone local to you who can remove it and install a more modern unit, which will cost a couple of hundred quid. I wouldn't bother trying to repair the old one - it will be quicker and cheaper to simply remove and replace it.


Oli.

ETA: Fitting car alarms is very simple if you are practical and can follow a simple circuit diagram. You may need to get it 'inspected' afterwards if your car insurance needs a certificate of installation though. A hunt of ebay for 'Thatcham Category 1 Alarms" will find a number of different ones to spend your money on if you want to go that way.
 
Cheers Oli. Kind of thought as much. This one is as old as the car and works faultlessly except these annoying incidents. I still have 2 functioning key fobs and in all my years I've never seen any evidence of its installation anywhere. So it's been a good job with seemingly a decent system. Could never ascertain if it was factory or dealer fit but I suppose that doesn't matter now but I'm loathed to rip it out. The key fobs say Serpi Star if that helps anybody ID it. I do recall in the old days of the Harry Moss weather report self fit car alarms there was a sensitivity switch somewhere and was hoping this may offer similar. Long shot I know but hence asking nonetheless.

Cheers

Stuart
 
Don't think that was the factory (dealer) original, my 90 and 91 both have/had the H&P unit which arms the alarm with the (key) door locks and the immobiliser is on the steering column with the chip to insert - If it was related, there is usually a box near the battery that controls the sensitivity of the ultrasonic sensors which are mounted by the rear quarter windows. It could be an upgrade to remote activation so worth a look in front of the battery. Otherwise most units do have adjustable sensitivity, it will just mean locating the sensor control box.
Tony
 
Whoah - that IS old! 'Serpi Star' would be a 'Waso Serpi Star' with a chunky rectangle-with-the-corner-cut-off fob, non? I had one on an old Mk1 Golf GTI I owned when I was 18; that it is still working at all now means that it would have been very well installed, which is quite impressive. I don't recall whether there was a sensitivity switch on it - sorry. I think that that unit wasn't Thatcham Approved as I seem to recall having to have a Clifford alarm fitted when the Thatcham bru-haa-haa came in.

As Tony said, that almost certainly won't have been factory or dealer fitted - it's almost definitely aftermarket.


Oli.
 
from what i can read on the interweb

Tech-Tronics Limited in Manchester can still do fobs and stuff for the serpi alarms
0844 3723003
 
Yes correct on all counts chaps! Key fob described perfectly and it must be after market. I gave up trying to match it to a model number for the alarm system last night. I will give Tech-Tronics a call and see if they can help.

Interestingly my car had the "blank" console switch, which I believe toggled ultrasonics for the factory alarm on and off, with a chopped piece of loom on it. But there is no evidence of a slot for a chip to go in ever having been there.

I will report back. Suppose it is amazing it still (mostly) works fine.

Stuart
 
So after further investigating this evening there is a rather large alarm box next to the siren! Oops. It has 3 sensitivity switches marked P1, P2 and P3. I have set them all to minimum. Also has a BUZZER switch. This was set to OFF. Left it there. There is also a key turn on/off switch marked ZADI. I have no key for this. It is obviously on. So fingers crossed the sensitivity switches does the trick. They were all previously at max.

Stuart
 
2ns0riw.jpg


This is the alarm box I would think. I tried adjusting the screw on the little box, bottom right, made no difference. I then realised that the alarm box had little rubber covers marked P1, P2 and P3, which I prized off and twisted the little adjusters fully anti clockwise. So far so good but not celebrating yet!

Also noted siren (at least I think that's the siren!) has a vac pipe. Is any of that set-up standard or totally after market?

Stuart
 
I think you are right. Cunningly shaped like a siren! The "siren" must be on the hidden end of the alarm box. Screaming abuse at the blower motor when it gets agitated! It is one very, very loud noise when it goes off. The blower motor must be completely deaf by now!

So what is the little box with the screw on top, mounted between the vac canister and bulk head? It has an earth, and a blue wire coming out from it with what looks like a double blade fuse housing, with no blade fuses in it? It seems to connect into the loom from the charging post and looks distinctly factory?

Stuart
 
that is the connection post that is a replacement for the LHD cars that have a battery live terminal up there,

it joins the ABS circuit to the starter motor and then a direct link to the battery, so yes the ABS is powered up all the time.

you an use the post as an emergency get power into the car to open the hatch
 
Thanks Martin. Yeah recognised the post but never realised it powered the ABS full time. Every day a school day. It's the little rectangular box, to the right of the vac canister, that I have no idea what it is. If you look closely it has an adjuster screw on top.

Incidentally the alarm has not went off since I moved those 3 adjusters fully anti clockwise. It might never go off again right enough even if somebody is stealing it! I'll wait a few weeks before I celebrate!

Stuart
 
wvpi6a.jpg


It's this Martin, that I haven't got a clue what it does. It has an adjuster screw moveable with a flat blade screwdriver.

Cheers

Stuart
 
that could be the adjuster for the ultrasonics, is it connected to the alarm I can see the wires sort of,

be interesting to follow those
 
It doesn't seem connected to the current alarm. It is earthed to chassis between itself and the bulkhead, blue wire. It then has a blue wire with what looks like a dual blade fuse carrier, with no fuses in. It then carries on into the loom with the cable from the post. I'm guessing whatever it was is redundant, and quite possibly from the factory alarm set up. Curiosity does get the better of you!

Stuart
 
I would personally remove any crap that just does not need to be there, just one more failure point removed
 
Yeah i agree but can't say with any certainty what it is/does and it looks factory. So I'll leave it be unless someone can positively ID it.

In other news alarm has behaved impeccably since I moved those switches so all good!

Stuart
 
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