Alarm siren question 2001 9-5

[QBee]

Just bought above car, on the dash I have the message to check the alarm, and if I lock the car, sometimes the alarm starts going off and won’t stop until it has done a set number of cycles (about 10?).

I live in a decent area, and don’t leave stuff in the car, so am not worried about having a working siren. With the car lock, unlock and work if I remove it, and will the car still immobilise as normal?

[jagnet]

Yes, the security will all work as normal other than not having a siren.

The most common cause is low battery voltage within the alarm unit from the two CR17335 lithium batteries, but cracked solder joints and bad capacitors can also be an issue. They're inexpensive and relatively easy to fix if you're handy with a soldering iron: https://youtu.be/ibEWHXE3fSI

[QBee]

I have only soldered twice in 65 years, but did successfully bypass a burnt out connector on a heater control unit the last time (and it worked!), so maybe I will give it a try.

Will the check alarm message disappear from the SID unit if I remove the siren? Or is fixing it the only way to get rid of the message?

[jagnet]

If you remove the siren unit then it'll throw an alarm fault message on SID each time on start up, but that can be disabled using Tech II to save having to clear it each time.

I'm not sure if faulty sensors could also cause similar symptoms, but I know that an overhaul of the siren unit fixed my random alarm problems. Switching the alarm to door sensors only by pressing the Night Panel button before locking the car disables the glass break sensor, so it might be worth trying that before getting out the soldering iron.

[QBee]

Thanks. I will try that.
It’s a lovely car, only £990, 85,000 miles. 2002. 2.3 SE auto
I have cleaned the strainer and changed the oil, bought a heater valve to cure that problem, and it is running really well. Tidy car, heated leather seats, good paint, tow bar.
Just an aux belt change tomorrow and sort the alarm and all will be fine.

Edited by QBee on Wednesday 19th June 22:01

[jagnet]

that looks well looked after.

[QBee]

Very little evidence of Braille parking for a change. When I went to pick it up from the dealer the previous owner was actually there, getting a minor fault with her newly acquired BMW fixed. So we had a chat. Only thing she didn’t tell me was that the oil light came on in heavy traffic, but the oil change and strainer clean has fixed that. Car is spotless inside and drives beautifully. Delighted with it. I love the 98-02 9-5 the best of all of them.

It will be pressed into Service towing my TVR on its trailer to track days, as well as being my daily driver for work, dogs and grandchildren.

[QBee]

Just a note by way of thanks for all your help with this. It was much appreciated.

I finally decided yesterday, after more random siren events, to remove the siren from the car.
Looked up the "how to" on Yooftube, and set about it.
First problem was the wheel was stuck to the hub - garage mechanic friend suggested putting three wheel studs back in loosely and dropping the car off the trolley jack as hard as i could. At the second attempt this worked and I was able to get the front nearside wheel off.
The rest was simple - wheel arch liner undone (8mm, 10mm sockets and T20 torx driver) and moved aside, siren disconnected and unbolted (13mm socket).

Took the siren indoors and undid the screws, removed the board and stared at it. Couldn't see the capacitors, and the batteries were clearly soldered in. Despite what the Saab forums said about batteries at £10 the pair, today's truth is that they are £30+.

At this point my best beloved chirped up with "why don't you take the siren off the black car that you have pensioned off, and put it on the silver one?"
Why didn't I think of that?
Outside again, same process on my now defunct 2006 Saab Aero, fitted the siren to the silver car and reassembled it. Put the tools away.

Started the car, and the "service theft alarm" warning came up on the SID. Bugger.
Inside again and started searching Saab forum threads for how to tell the car it had a new siren.
Finally spotted it after 30 minutes searching - "disconnect the car's battery for 10 minutes".
It worked.

So all evening I was feeling ridiculously pleased with myself - I had actually successfully managed a job on a car for the first time since I changed the auxiliary belt and alternator on my TVR, three years ago.

Little things.....