Based on suggestions from other forum members I have finally fixed my siren. I thought I'd show how I did it so anybody else could do something similar if they wanted to.
Basically, the siren will sound on its own when the internal batteries drain below a certain level (seems to take around five years). A new siren will cost almost £200 so that's a no-no for most. The batteries are unfortunately not available in the UK or Europe. There are similar batteries available, but they are NOT the same and will cause problems fairly quickly.
I have now fitted an external battery box using CR123A photographic batteries which have similar characteristics to the original spec batteries. They are easy to get hold of anywhere.
The parts used are as follows. From RapidOnline: IP65 rated box (ABS Clear 65x60x40), CR123A battery holder. From Maplin: switch (type E - which was all they had in stock which was suitable), waterproof switch cover. I also used some twin-core cable suitable for automotive use (hot/cold resistant) and automotive silicone sealant. (A switch isn't actually necessary, but I wanted to be able to disconnect the batteries instantly, just in case.)
The box itself cannot be too big or you will not be able to pass it through the hole in the wing. If in doubt, try it first. Make sure the box is waterproof. If it states IP65 rating then it should be fine.
If anybody needs just the CR123A battery holders then PM me as I bought a load (well, 30) as they were so cheap compared to their standard delivery charge.
If you need to see how to get to the siren and take it apart see here for the instructions I originally used.
The original orange CR17335 batteries (on the left), CR17335SE batteries (fitted) which DON'T work and some CR14335BL batteries which did work for a while.
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You'll need some form of soldering tools (soldering iron and, if possible, a desoldering tool).
![Image]()
Here's the siren taken apart, showing the cable soldered onto the positive (lower left) and negative terminals on the underside of the circuit board. I made sure the cable wouldn't snag or be squashed by routing it around one of the sirens. I drilled a hole in the bottom of the siren and once everything was in place I sealed the hole with silicone sealant.
![Image]()
The siren with the circuitboard in place. Make sure you replace the (circled) jumper on the circuitboard if you removed it.
![Image]()
I drilled two holes in the side of the box, one for the switch and one for the cable. The switch has a waterproof cover and the cable was sealed with silicone sealant.
I soldered leads to the battery-holders so they are in series and then to the switch fitted in the side of the box. Positive on switch to positive on battery one, negative on battery one to positive on battery two, negative on battery two to negative on switch. Take care with this and double check the polarity as you don't want to get this wrong. Then solder positive to positive (and negative to negative obviously) in the cable from the siren to the switch.
The picture shows how I 'glued' the battery-holders to the base of the box using the silicone sealant and being held by a clamp.
![Image]()
The finished box with batteries in place.
![Image]()
The finished article. The cable is approx 40-50cm in length to allow the box to be passed through the hole in the inside wing from the wheel-arch side (a helper is useful for this) before fitting the siren back in its place in the wing.
![Image]()
Lastly, I fixed the box using outside sticky fixers (having cleaned the surfaces first). It just tucked nicely under an earthing cable for a bit of extra support. I've marked the cable which goes to the siren in red.
![Image]()
That's it. Enjoy the silence, but also the knowledge that if someone does tamper with your pride and joy, the siren should sound.
Basically, the siren will sound on its own when the internal batteries drain below a certain level (seems to take around five years). A new siren will cost almost £200 so that's a no-no for most. The batteries are unfortunately not available in the UK or Europe. There are similar batteries available, but they are NOT the same and will cause problems fairly quickly.
I have now fitted an external battery box using CR123A photographic batteries which have similar characteristics to the original spec batteries. They are easy to get hold of anywhere.
The parts used are as follows. From RapidOnline: IP65 rated box (ABS Clear 65x60x40), CR123A battery holder. From Maplin: switch (type E - which was all they had in stock which was suitable), waterproof switch cover. I also used some twin-core cable suitable for automotive use (hot/cold resistant) and automotive silicone sealant. (A switch isn't actually necessary, but I wanted to be able to disconnect the batteries instantly, just in case.)
The box itself cannot be too big or you will not be able to pass it through the hole in the wing. If in doubt, try it first. Make sure the box is waterproof. If it states IP65 rating then it should be fine.
If anybody needs just the CR123A battery holders then PM me as I bought a load (well, 30) as they were so cheap compared to their standard delivery charge.
If you need to see how to get to the siren and take it apart see here for the instructions I originally used.
The original orange CR17335 batteries (on the left), CR17335SE batteries (fitted) which DON'T work and some CR14335BL batteries which did work for a while.
You'll need some form of soldering tools (soldering iron and, if possible, a desoldering tool).
Here's the siren taken apart, showing the cable soldered onto the positive (lower left) and negative terminals on the underside of the circuit board. I made sure the cable wouldn't snag or be squashed by routing it around one of the sirens. I drilled a hole in the bottom of the siren and once everything was in place I sealed the hole with silicone sealant.
The siren with the circuitboard in place. Make sure you replace the (circled) jumper on the circuitboard if you removed it.
I drilled two holes in the side of the box, one for the switch and one for the cable. The switch has a waterproof cover and the cable was sealed with silicone sealant.
I soldered leads to the battery-holders so they are in series and then to the switch fitted in the side of the box. Positive on switch to positive on battery one, negative on battery one to positive on battery two, negative on battery two to negative on switch. Take care with this and double check the polarity as you don't want to get this wrong. Then solder positive to positive (and negative to negative obviously) in the cable from the siren to the switch.
The picture shows how I 'glued' the battery-holders to the base of the box using the silicone sealant and being held by a clamp.
The finished box with batteries in place.
The finished article. The cable is approx 40-50cm in length to allow the box to be passed through the hole in the inside wing from the wheel-arch side (a helper is useful for this) before fitting the siren back in its place in the wing.
Lastly, I fixed the box using outside sticky fixers (having cleaned the surfaces first). It just tucked nicely under an earthing cable for a bit of extra support. I've marked the cable which goes to the siren in red.
That's it. Enjoy the silence, but also the knowledge that if someone does tamper with your pride and joy, the siren should sound.
