remote central locking aftermarket problems

[ash_on_mtb]

I've picked up a remote setup to add into my 91 80 series, as it already has central locking. The kit is a jay car sold setup which comes with a wiring loom, control box and remotes. The theory goes that the wiring loom gets connected to the actuators, power shoots down, trips the locks, all happy.

Sadly, and as best as I can work it out, the new system sends positive pulse down the 'unlock' wire, to fire the motor one way, and a positive pulse down the 'lock' wire to unlock. Thats all well and good if you buy their actuators, but to add it into the existing central locking system, well the pile of fuses tells the story.

Without understanding much, I can only figure that the locks in a 80 are negatively switched, which is more a snazzy term than something I understand, but basically the negative feed to the locks is constant until its cut which trips the lock.

How the do I get the system to add in and work.....?? I'm baffled. Does it involve a relay somehow? Can anyone please please shed some light on this one, as its consumed hours of my time already and I just don't understand enough to develop a solution.

Cheers all!

[ash_on_mtb]

has anyone jagged around with the locking components and can help us out??

[chimpboy]

I haven't seen that specific kit but I am almost 100% sure that you can define whether the signal is positive or negative. You have a wire that you feed the signal into (ie connect it to +ve or -ve), and then the unit sends that signal (whichever it is) to the existing system.

If you double check and it definitely doesn't have this facility then it would not be too difficult to use a NC ("normally closed") relay to do this job. A NC relay works sort of in reverse of a normal relay - when there's no signal to it, it acts like a switch that's on. When it's tripped, it OPENS the switch ie disconnects the circuit.

I am assuming your description "the negative feed to the locks is constant until its cut which trips the lock" is accurate, it sounds unusual but toyota wiring often is.

Basically, what you would do is cut into the existing -ve feed and put a normally closed relay in there. Then you would use the +ve signal from your new remote locking unit to trip that relay - when the relay sends a signal, breaks the negative feed.

You could also use a double-throw relay and disregard one terminal on it, eg http://www.jaycar.com.au/productView.asp?ID=SY4070

What you would do is cut into your existing wire, and connect one side to terminal 30 and the other to terminal 87a. This restores the circuit you've just cut.

Then you would connect terminal 85 to ground, and terminal 86 to the +ve signal from your new central locking unit.

Those terminal numbers are right for the jaycar relay but may differ for other brands.

Again, this is based on your description of the existing system and I can't vouch for that one way or the other.

[ash_on_mtb]

thanks HEAPS for your suggestions!! Thats basically what we will attempt to do, but it spins my head pretty hard, the whole negative swithing thing, and I have to have it in my hands to get my head around it. But it sounds like the track we will go down. Thanks for taking the time to point us in the right direction, I'll see how we go!!

cheers,