#ProjectC70 has a new Alarm Siren!

For the last 6 months since #ProjectC70 started, the Alarm decided to pack in, what it would do was flash the hazards but it wouldn’t make a sound which only meant one thing – the siren was buggered!

After looking online at the Forums i found out it was a common problem and it was hidden in the O/S/F inner wing above the washer bottle, what would happen is the battery pack inside the siren casing would run out of power and leak it’s acid onto the circuit board causing it to go faulty – time to get to work!


I started off by jacking the car off the ground using the cars own jack – yes i know this isn’t the safest option but it’s the best jack we’ve got until we upgrade which we’ll be doing hopefully soon.

After jacking the car up, i removed the wheel using my very powerful and trustworthy 400nm 1/2 drive buzz gun & a 17mm high impact socket which made things so much easier than a conventional Breaker bar, Spider and Torque wrench – the wheel was off within seconds!

Once that was done, i removed the right hand side of the wheel arch liner by removing 2x 10 mm grommet style bolts and 3x T25 Torx Screws, once removed i peeled the liner back and got into where the old alarm siren was.

All it took to remove it was two 10mm bolts and a flat headed screwdriver to remove the electrical connection, reasonably easy to get into to be honest compared to more modern cars where they’re hidden in all sorts of places.

A few days after the old one was removed, i took it to Motherwell College where i currently study to find out exactly what caused it to fail, after about an hour of stripping it down and looking into it thanks to an Auto electrician in the college we found out that the battery pack was the culprit and had ran out of power, on top of that it had leaked out some battery acid onto the circuit board which meant that even though the siren was working and the circuit board was getting power it was toast so i had to get it replaced.

After finding one on Ebay and waiting until it arrived – which was today, it was time to fit the replacement which was the reverse of the strip down, alarm went in and got bolted into place, liner got put back into place and the wheel eventually went back on, once it was back in we decided to test it to see if it was working and after a while of playing around with it, it sprung into life and finally made a noise after 6 months of complete silence – it was fixed!

Best bit of all however was the price, now Volvo themselves were charging £170 for a new one and while that isn’t too bad for a new one whatsoever,  i got mine for £20 & Free Postage, that’s a £150 saving which can’t be sniffed at, and because i removed and refitted it i don’t pay labor costs at all, just the replacement part.

So finally after six months or so, she is safe against thieves and carjackers and the likes which is only a good thing. Not bad going for £20!

Here is a video of the new siren working: ​


Hope You Enjoy!


By Alex Jebson


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