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Problem when connecting alarm to indicator circiut
Posted: 04 Mar 2007, 12:53
by Bilbo Blue
Trying to fit a Cobra Cat 1 alarm and imobilizer to my 1990 type 25.
Alls going well untill I connect the unit to the indicator circit and there is a dead short. Ive been told that normaly on a vehicle there is a perminant earth to the indicator bulbs and they are switched on with the live fed coming on and off. VW seem to do things different where there is a perminant live fed to the bulb and the earth is switched on and off. When the alarm is activated and it tries to send a positive signal to the indicators there is a dead short.
Anyone got over this problem before?
Posted: 04 Mar 2007, 14:43
by "WEAZLECHIN"
wire it to the headlights, it worked on my audi.
Posted: 04 Mar 2007, 15:52
by Bilbo Blue
Would have thought that would be too much load on the wireing loom of the alarm. They areonly small cables. Thought of the side lights but the're switched the same as the indicators ie on the neg side.
Posted: 04 Mar 2007, 16:02
by mcalp
Use a relay. Connect the wire from the alarm to one side of the coil, the other side to earth and an earth feed to the relay switch terminal and the other side of the relay switch to the indicators.
When the alarm is activated it will put a current across the relay coil and close the relay switch thus connecting the indicators to earth and completing the circuit.
Re: Problem when connecting alarm to indicator circiut
Posted: 04 Mar 2007, 17:38
by Fox McIntyre
Bilbo Blue wrote:Trying to fit a Cobra Cat 1 alarm and imobilizer to my 1990 type 25.
Alls going well untill I connect the unit to the indicator circit and there is a dead short. Ive been told that normaly on a vehicle there is a perminant earth to the indicator bulbs and they are switched on with the live fed coming on and off. VW seem to do things different where there is a perminant live fed to the bulb and the earth is switched on and off. When the alarm is activated and it tries to send a positive signal to the indicators there is a dead short.
Anyone got over this problem before?
Nope, shouldn't be cause thats exaclt how my alarm works my indicators, it sends power into the circuit and flashes them that way, the indicators have a permanent earth and a modulated 12V input when switched on, you should get no problem provided you are connecting your alarms 'flash' wiring to the + not - side of the indicator circuit. Depending on where your alarm is (mines under the engine hatch) I just ran my 12+ alarm feeds to both rear light clusters, removed the plugs, removed the + indicator wiring plug pin and soldered the alarm wiring to this, does the job perfectly with no problem!