Alarm Controlled Central Locking - Help Needed

[Mike_H]

I found this on an add for the same alarm but another supplier...

"Note that the lock/unlock outputs on this alarm are low current negative (500mA), to control the central locking on most cars you will need two 30 Amp relays"

I suppose the best thing to do is get the multi meter on them for current, as have only measured V thus far....if it ever stops raining that is

[g8dhe]

Well measuring the current won't actually tell you anything, the current taken will depend on what load is connected.
You need to find out if there are relays or not in the box in this situation. What is the make and version you have bought ?

They way the relays would work is as below;

When nothing is being pressed then both relays are in the position shown and the Door Actuator does nothing as it has no power connected to it.

When you press the Open button a short pulse is applied to the left Open relay that makes the contacts move to the position shown, +12 volts is applied to the Actuator on one side whilst the other side is still connected to 0 volts so a current flows and pulls the actuator downwards. It then releases at the end of the pulse.

When the Close button is pressed then a pulse is applied to the righthand relay and it closes connecting the other side of the actuator to +12 volts, whilst the other connection stays at 0 volts and hence now the current flows in the opposite direction and pushed the rod up. Again at the end of the pulse it releases and returns to the centre position.

[Mike_H]

Thank Geoff...I have tried fitting the non-Bongo door actuator via a 4 pin relay and the other side of the actuator to 12v...hey presto its works, but only one way obviously - I have no idea where to start with using 2 relays. Unfortunately has gone haywire as now the the starter wont work aarrrrrrgghhh! - after 3 weeks of faffing about I'm on the brink of ripping the whole thing out & paying someone to fit another brand...might feel different after a couple of G&T's later

PS - I haven't posted the alarm type on "open forum", but more than happy to PM you if this helps...its not a particularly good/costly make but it did come recommended(?)

[g8dhe]

Well the relays will have to have 5 Pins you need changeover contacts not simple make/break contacts see here you will need relays of the type R20Bc/d and you would need a pair of them.

There is no problem in posting the alarm type, its not advertising, if we can find data about it then others will know how it will need to be used.

[Mike_H]

Is this the set up I need, and replace the 30 connection with those to the door motor wires?



Clutching at straws now!!!

[g8dhe]

OK, close / similar but try this;


Both 87 and 85 connections on both relays to +12volts.
Both 87A connections to Ground.
86 on the Unlock goes to the Blue wire on your controller, and the White wire on controller to ground.
86 on the Lock goes to the Green wire on your controller, and the Black wire on the controller to ground.
30 on Unlock goes to the Red from the two wire actuator.
30 on Lock goes to Red/Black from the two wire actuator.
Its possible you might need to reverse the two 30 connections, as we don't know which way round the actuator works so if it locks when it should unlock reverse the connections!

[Mike_H]

Success with the relay's - superb info Geoff!, the original door locks will now lock/unlock with a negative trigger....only trouble is that the alarm doesnt appear to be giving any signals now (I was getting 12v + pulse before, which sounds odd as both the instalation info & most alarms appear to give a negative trigger???) so now completely baffled.

Any guidance on testing the negative triggers...I assume 12v through meter +ve, then -ve of meter on the end of the alarm trigger wire, press fob button should = 12v pulse - swap lead and test other way - tried it and got nothing???

Will make one last ditch attempt in the morning and if no joy will rip the blasted thing out and start again with something else...dont you just love car electrics

[g8dhe]

Actually a -ve trigger doesn't mean a negative voltage as such it means that the trigger is a pulse that goes downwards from +12v to 0v, so when you first look at the signal it will be sat at +12v and then the pulse is a 0v one for the duration.

Actually a minor change to the above circuit for the door release, whilst the above works, it will also draw an excess of current when not in use as both relays are operated, the revised diagram below is below the only change is to the signal wires from the Sniper X1 controller which goto earth;

Both 87 and 85 connections on both relays to +12volts.
Both 87A connections to Ground.
86 on the Unlock goes to the Blue wire on your controller, and the Orange wire on controller to ground.
86 on the Lock goes to the Green wire on your controller, and the Pink wire on the controller to ground.
30 on Unlock goes to the Red from the two wire actuator.
30 on Lock goes to Red/Black from the two wire actuator.
Its possible you might need to reverse the two 30 connections, as we don't know which way round the actuator works so if it locks when it should unlock reverse the connections!

[Mike_H]

......NEWS FLASH.....Man seen running naked down the road, waving a multimeter and yelling "Eureka, Eureka my central locking works...upon questioning by the Police he claims to belong to some strange sect by the name of Bongonliers - likely story.

It transpires that I had blown one of the circuit protection tracks on the PCB, once re-soldered, hey presto it works a treat.

Thanks for the expert assistance Geoff.

[g8dhe]

That makes a lot more sense, you will probably find you don't need the additional relays now either, I couldn't see that a commercial unit would need them but as it seemed to work ....