Alarm system error?

Type: Volvo S40 1.6, original volvo alarm system, year:1998

Failure: When I lock the car with the remote control the traffic indicator start flashing (like distress signal) until I unlock the car.
Any idea? How can I fix it?

Thx:

PSZ

[mrooke]

Hi PSZ,

I'm having exactly the same problem on my 1998 S40 T4 CD.

Please, does anyone out there have any idea what the cause is?

Thanks in anticipation,

Mick.

Try the bonnet lock microswitch ,thats the favourite thing as its right in the weather.
Its set on the locking mechanism and is connected to the system via a lead which if you follow towards the engine side you will find a plug in the cable.
Pull it apart and if its not corroded then the switch is probs knackered.
You can either sell a kidney and buy a complete new lock assembly,or drill the rivets out and fit a switch from maplins,or as i did just bridge the contacts in the engine side of the plug and try that,if the alarm is then ok its the switch.
Ive just left mine with the switch wires bridged and its fine.

[mrooke]

Thanks for your reply Vinny J, I have already tried that, as I found that possible solution, on this forum, in a previous thread.

The alarm siren now is 'chirping' quite regularly, even with the alarm disarmed.

Also, the fault of the indicators flashing is not always the case. Sometimes it arms normally but then after a few hours, I get rudely awakened by the alarm going off. That is quite out of character for this alarm, as it's never had a false alarm prior to this light problem.

Reading through previous threads on this issue, my battery was also replaced mid February, (original battery lasted 7.5 years, very impressed)), about the same time that this problem started. I see that this has occurred to at least one other owner.

Any other ideas, or do I have to just bite the bullet and take it into a dealer?

Thanks Mick..

assuming you have the stereo code then just try disconnecting the battery for a couple of hours,when you reconnect it put the earth on last for some obscure reason this can make a difference,
If you take the battery right off and have a look at the alarm siren they possibly have done something to the connections or the plug as it sits just underneath the battery.
When you reconect it leave it without the doors locked for a few minutes before locking it,if its inside a garage then overnight would be better for both of these stages.
Good luck

[mrooke]

Thanks Vinny,

I'll try that when I get back from holiday and I'll let you know if it works.

I have already tried disconnecting the battery for 30 minutes, to no avail.

It's a shame that the haynes manual says nothing much about the system. i never even knew where the siren was and now you have me thinking about that.

Regards,

Mick..

yes it sits right under the battery and the plug on the lead goes straight into the siren,which is a bloody silly place to put it as any spillage of liquids above it would stand a good chance of getting in places it shouldnt.
pull the plug off the siren and look at the connections as it sends signals backto the computer to tell its status,i think theres 6 or maybe 8 connections on and all in use.
The haynes manual is ok but for all the stuff the manual does'nt cover you really need a vadis dvd which has all the parts lists in as well,its what the stealers use for pretty well everything.
I hope you enjoy your break.

[mrooke]

Hi Vinny,

Thanks for your advice and the holiday wishes, which was good.

Today, I removed the battery and it's mounting tray. I disconnected the siren and had a good look at the pins on the connector on the siren and they were in very good condition. I reconnected the siren, refitted the tray and battery and left it disconnected for 6 hours or so.

Then I reconnected it and left the doors unlocked /disarmed for about 3 hours. I armed the car and the lights never flashed. I then tried to open the drivers door and it opened and the siren went off. That shouldn't have opened when the alarm was armed. I tried again and it did the same. Then I sat in the car and armed it and then I noticed that the drivers door inside lock indicator (or whatever it's called - the piece of plastic that goes up when you unlock etc) never moved down as far as it should / as the others. I pushed it down as far as it would go, disarmed it and got out. Then I armed thr car again and attempted to open the drivers door and it never opened. I left the alarm armed for about 4 hours and no false alarms.

It's now outside my house armed and here's me hoping that it won't wake me up with a false alarm.

Thanks for your help and I'll let you know what it's like after a week or so.

If any one else has this problem, just try the above, it's not difficult and it's worth it if it cures your problem.

Regards,

Mick..

[mrooke]

Further to the above, the alarm is now playing up again and the siren chirping away while it's disarmed.

Yesterday, I removed the siren unit and dismantled it in the bay. The unit is all nicely sealed inside with some sort of resin, to prevent ingress of moisture. I decided that as this unit contained some form of battery pack, that it's very possible that that is what was causing the problem, afterall, rechargeable batteries will eventually fail, especially after 7.5 years in a 'harsh' environment. I removed the resin around the 2 cells. I checked the voltage of them and one was about 0.9volts and the other 2.5volts. That just confirmed that this could well be the problem. I opened up the cells and they were full of corrosion.

I've now ordered a 'used' siren unit, as a new one was quoted at over £170 + VAT.

I'll let you know how it goes.

Mick

[mrooke]

I fitted the 'used' siren unit today and all is well. No flashing indicator lights, no chirping of the siren when disarmed.

I purchased the unit (part No 30820037) through:-

http://www.partsgateway.co.uk

Total cost including delivery was £32.90

Took about 15 minutes to fit.

UPDATE:

After 8 days, all seems to be working fine.