Adding switches to existing door locks.

[Muad'Dib]

I need some wiring help. Im usually pretty good about this myself, but i need some help here.

Here is a basic image of whats going on...



I tried to show in the drawing the existing wiring to all four doors (small squares). Both unlock and lock work from the alarm. The Square lock and unlock boxes in the picture are relays that dont pass current until the alarm activates the coil side of the relays.

I would like to add two switches to activate lock and unlock within the cab. One switch on each front door. Thats what the up and down arrows represent.

Now i am unsure on how to tap into the existing wiring to activate the locks with the switches. Does anyone have some suggestions?
My idea was to just wire up each switches lock and unlock output wires to the existing lock and unlock wires (after the relays) that are already in place. I can see this working just fine with one switch, but what about two switches? Im sure it would wire up fine, and work fine with two switches, but what happens if some how both switches get pressed one way or the other at the same time? Or even press one of the buttons on the remote at the same time as pressing the same way on one of the switches? I would assume i would blow a fuse or something... thats where im getting confused. Im sure its simple... just trying to get my mind wrapped around it. Either that or im thinking about it all to hard!!

HELP!

[amcinstaller]

is this a factory or aftermarket alarm? which year of jeep?

if its an aftermarket, the easiest way would be to ground one side of the switch (new ones to be added) and hook up the other side(s) to the respective action (lock or unlock). chances are the alarm module will put out a ground trigger to the relays. if its a factory system, depending on the year it can get a little sporty.

as for all the rest, it depends on the system. if its a "5 wire" system, theres two relays and depending on which way the lock is going, one relay will change a side of the actuator wiring to positive. if both get hit at the same time, the actuator sees positive on both sides of the wires, and it does nothing. remember, in this system, both wires are ground at rest.

[Muad'Dib]

Its an aftermarket alarm with aftermarket door lock actuators (two wire like oem).
The switches im going to be using are OEM. The switches can easily be wired to pass 12v to lock / unlock depending on which way i throw the rocker on the switch.

Just as i said in my first post, there are two relays. One that is for lock and the other for unlock. Pin 87 (usually the non active pin on the relay until the coil is energised) on each relay are wired to all the locks actuators. When the alarm arms it energises the coil for the lock side and locks all the doors. When it disarms, it does the same for the unlock side. (It all works great)

My goal is to tap into the wiring at pin 87 (to the locks at each relay). When i flip the switch it will do the same thing the alarm does currently. The switch will be basically acting as the coil on the existing relays.

What im worried about is if say i sent 12v to the unlock side from one switch, and accidently do the same on the other switch (or disarm the alarm... same kinda deal) .. i can only see bad things happening there.

[Muad'Dib]

Well after doing alot more reading, it appears that i need to find out how the locks are triggered for sure. It appears that they can be wired multiple ways. I just thought that they would be wired they way i explained... but it looks like im probably wrong. Im betting its something like this:




They can be postive trigger, negative trigger, reverse polarity .. etc. That will impact how i wire in the switches.

[amcinstaller]

first off, let me assure you, if you hook up between the alarm and the relays, no bad things will happen, even if your drunk buddies are dickin with the switches!
smart money is on the reverse polarity (5 wire). MOST aftermarket systems only have a negative trigger output for locks at a whoppin 500 milliamps, IF that. all youd need to do is wire 12+ or gnd to the one side of the switch (dependin on the alarm output whip out your meter to check it), and bring the triggers to the relays. and you shouldnt have to do anythin fancy, just splice on right between the alarm and the relays. if you tell me which alarm system it is, ill tell you what colour wires and polarity (but i bet you know that already dont you! )

also, you could use your test light. if it lights up when you operate the locks its positive, if you operate the locks by touching the wire its negative (while connected to ground)

oh, and thats probly EXACTLY how its wired

[coas]

See if that help.

http://www.esnips.com/doc/a1c24fbf-89ac ... tion-Guide