I'd Like to DIM Car alarm.

[Guest]

Since it's recession here in NZ. We all have to be smart about spending our money. I have recently bought a car alarm system from trademe which is good for it's price. I have been looking every where to get it fitted. They normally cost up to $150 + . So I thought to my self that I could just do it myself. So I got a few questions here:

Do I need a door actuator and relays to operate a wireless entry?

Wiring diagram for subaru legacy 96?

Any suggestions or comments would be highly appreciated

[Durty-Sanchez]

1. If by wireless entry you mean remote-unlocking then no, so long as your car already has central locking. Subie's do some odd things though with voltage transitions to get stuff to work... been a while so can't recall exactly. If you mean to completely open the door then yes you will need something to push it open.

2. I don't know of any, but it's not exactly rocket science. Nothing a test light or multimeter cant tell you.

3. At $150 to get it installed vs how ever many hours it will take you it's not such a bad price to pay. Having said that though you'll learn a bit about how it all works. Even the best alarm can be crap and offer little protection if it's poorly installed. Try to immobilise the critical things (computer, fuel pump, AFM if you can) and make it as confusing as hell.

[Guest]

Thank you for the comments.

Just want to press the button to unlock and lock the car you know. Not completely open the door itself that would be too high tech for me. lol.

True, true subarus are complicated in their own unique way. Thats why they are so special.

heheh

[Joker]

DIM = DIY?

[Durty-Sanchez]

Do It Myself? Depending on what your alarm does you can reverse wire the door lock actuators so they work (from memory subies are wired to pulse negative rather than positive, but most alarms are set up to pulse positive to the actuators)... dont quote me on that though... g'luck!

[aim]

 Durty-Sanchez said:

from memory subies are wired to pulse negative rather than positive, but most alarms are set up to pulse positive to the actuators

Wut?

[Durty-Sanchez]

Pass, its been many years since my time as an alarm installer... but I seem to recall that subies are wired to negatively switch, where as most alrams are geared to positively switch. Don't quote me on it, just something that hangs in the back of my mind that *if* you ran in to you could say "oh hey... that guy said that would happen"

[aim]

No I mean, negative pulse... How does that make sense? Do you mean constantly live and the switch is an earth (ie negative?)

[suubyduuby]

96' Legacy should def have central locking (unless its been taken out of course) - so just a matter of finding the correct color-coded wire under the dash (should be relatively generic), splicing and wiring it the appropriate wire from the alarm.

I guess the biggest downfall to a DIY install is how easily the system can be bypassed. Not sure if the alarm you have bought has color coded cabling, but this can easily be spotted by a crook and quickly ripped out. Ideally if your alarm has no color coding on the wires coming from the control box, that is great (should have labels to guide installation though - make sure you remove these as you go!)

Just a comment to demystify negative/positive switching:

- Switching negative (or often referred to as low-side switching):

The relay/electronic switch when activated, switches with respect to ground. Ie. In the case of a door actuator, one wire would be permanently connected to +12V, the other to the switch. When the switch is closed (ON), a connection to ground is made, current flows and the activator/solenoid is energized.

- Switching positive (or often referred to as high-side switching):

The relay/electronic switch when activated, switches with respect to supply (+12V). Ie. In the case of a door actuator, one wire would be permanently connected to ground (chassis 'earth'), the other to the switch. When the switch is closed (ON), a connection to supply (+12V) is made, current flows and the activator/solenoid is energized.

As commented above, different car manufacturers use different supply rail techniques.

But I believe -ve switching is most common. Theory behind this is that power actually flows from - to +, not + to - (electron flow).

But yeah, getting back on topic.

- Do a clean job. Solder wire connections for best results or at least use high-quality crimp/bullet connectors (gold-plated etc). Appropriate tools make all the difference here.

- Check supply rails and polarity with a multi-meter.

- Try to hide wiring as much as possible - and avoid color coding.

- If you are wiring an alarm with a data-backup battery, be careful how you wire this into the engine bay. Try to avoid areas of high electrical noise ie. routing past distributor cables etc. Be careful where the cable is routed - keep away from hot engine areas.

[familyman]

 

. In the case of a door actuator, one wire would be permanently connected to I agree in full with your thoughts on that matter.2V, the other to the switch.

word filter really makes you have to think. Ha!

[smokn4]

hit up spark_38 for help i think he specialises in the electrical side of things...

and he's local.

[DRFVDR]

I dont know if this will be much help,but in my BF legacy when the alarm was installed,they wired it into the central locking control box,which resides behind the glovebox

[Guest]

Whoa thats all alot of infos. Cheers man. Yeah I have been looking for the central locking motor for ages i hear it somewhere on the front passenger side. cheers for pointing that out from behind the glove box. Well I will print all these out and see what I can do . Many thanks to you all.