mmboost

iTrader: (2)

The stock WRX alarm does not include the hood as one of its triggers. So, its pretty easy to pop a WRX hood without setting off the alarm (through vibration/tilt), especially if you have an aftermarket grill that's just made out of gutter mesh, or something similar. Well, I've taken a few precautions to make it a more difficult task. One method I've recently figured out is how to add the hood to the stock alarm set of triggers. The following instructions explain how to add the hood to the trunk alarm trigger.

This is written on a level of detail that I hope the generally electronically challenged can take a good hack at it.

Materials:

- 10ft of 14ga wire

- 1 quick connect tab set - the little flat tab that fits into the curled edge socket

- 1 quick splice - it wraps around a wire and taps it when crimped. You can slide a flat tab connector into it, making a T tap.

- 1 pinswitch - a spring switch that is electrically open when the hood is closed, and connects to ground when the hood is open.

- 1 diode with at least a 16volt threshold - this is to keep the trunk room light from coming on because the hood has been opened (Thank you Mulder @ i-Club!)

- Some dielectric grease

- Some non-permanent threadlock





Some of the details (e.g. exactly where to put the switch) are left out on purpose. This isn't so much to make my setup more hidden as it is to let you use your imagination and customize your own setup, making it a little more confusing to a would-be thief....


- Find a spot to place the pin switch so that the switch opens when the hood is closed. Drill a hole in a place where the switch post will not bang into anything as the hood closes. Make sure the switch isn't too high or your hood won't close properly (or at all!). Once you have a good spot sand a bit of paint off around the hole for a good ground connection. Put a bit of dieletric grease on the top of the hole if you have any around. This grease helps prevent corrosion and maintain good electrical connectivity. Drop the switch through and put a bit of thread lock (non-permenant) on it before tighting the nuts down. Triple check, close the hood. I put a bit of WD40 on plastic part of the switch.

- Strip about 3/8" off the wire and crimp the female tab (the curled edge) onto it. Find a good way to snake the wire from the firewall to where the switch is. A bit of dielectric grease on the conenctor, connect it to the switch and yer done with the hood.


- Back in the cabin lift up the center console section that covers the e-brake and security module. Sitting in the passenger seat, facing forwards, look down at the module. On the top row of wires, 2nd from the middle towards the drivers seat is a blue wire with silver bands. That's the wire which eventually makes its way to the trunk switch. Take a small, sharp knife and just cut through the wire's cover, a slice all the way around and separate it a bit with your fingers so you can see the copper wire peek a bit. Now take the quick-splice and put it over the cut you made. Crimp it down hard.



- Bring your pinswitch wire to the security module with at least a few inches to spare. Attach diode that has at least a threshdold voltage of 16 volts to the end of the line with the cathode (banded/marked) side towards the pinswitch. (Thanx for the tip Mulder@i-Club !). Its a good idea to cover the whole diode attachment with heatshrink tube to protect and strengthen it. Then attach the diode to the male (flat) tab quick connector. Put some more dielectric grease on it and connect it to the tap. And that's it.


Testing your installation (without pissing]your neighbors off):

Close all doors, etc and leave the hood open. Hold the pinswitch down with your hand and arm the alarm, continue to keep the switch down. It should arm normally. Disarm and let the switch up. If all seems normal you haven't broken anything

With the hood up and not holding the switch try to arm the system. You should get 3 beeps as though your trunk (or a door) was open. If it arms, the security module is not recognizing the switch. Check your connections and test again. If it does the 3 beeps put the switch down AND HOLD IT. Now the system should arm on its own. If it does, excellent... if not, that's really freakin' weird. If you're still interested in having a good relationship with your neighbors, disarm the system before letting go of the switch.

Any questions?

Have fun,

jason

DLUX WRX

iTrader: (1)

Good Post.
My Viper alarm alreay has hood protection, but its still prett cool .

Peaty

iTrader: (2)

Jason,

Can I cut and past that to our Scoobymods site? That's good info.

Peaty

mrruins

iTrader: (21)

mmboost...ingenius...
thanks for the alarm wisdom

mmboost

iTrader: (2)

Thanx for the kudos, guys. And Peaty, yeah sure, send it to Scoobymods, that's what it's for


jason

mmboost

iTrader: (2)

Oh peaty, I just thought, could you copy the images outright instead of just having links to my site?

thanx,
jason

Peaty

iTrader: (2)

Did it an posted, thanks

Mulder

This works, BUT-
As wired directly into the instant trigger trunk circuit, the hood switch will turn the trunk light on when the hood is opened. To avoid this, a diode can be inserted in series with the trunk circuit wire close to the security module, with the cathode end (band) pointing away from the module. The wire for the hood switch is then connected to the circuit between the diode anode and the module. The hood and trunk switches will then be fully isolated from each other.

mmboost

iTrader: (2)

You're absolutely right... duh, didn't even think of this when I was looking at the schematics. And, that's exacty the right fix.

Its pretty funny that I hadn't even thought of it because I have been getting feedback into the door-open indicator from my pager system. And just after I put the hood pinswitch in I put a diode on the pager system to stop the feedback for the doors because I already had the console open... didn't even occur to me to do the same for the new switch, heh.

jason

p.s. I've edited the original post with Mulder's suggestion.

Mulder

Glad to help you catch that one. You can also add other instant-trigger devices the same way, such as a motion sensor. However because the alarm isn't really set up for it there won't be a delay in arming that sensor so it's possible that if the car is shaking slightly (such as from slamming a door or the trunk) when the alarm is armed it might go off. The way to avoid that is just to wait a few seconds before arming.

iNfEk

iTrader: (33)

wow... this is pretty cool.. since I do NOT have the factory alarm how do I go about hooking this up for my Viper Alarm? What is the wire tha tyou are tapping into?

Mulder

I don't know the specifics for your Viper but it probably has an available instant trigger input for this purpose, you can use that. Consult the manual that came with your alarm if you have it.

mmboost

iTrader: (2)

I was thinking about it the other day, and I think the DIODE idea will not work. Here's why:

The security module seems to be, for the most part, between the light and the switch. This is true for the doors and the combo meter door-open light, and I suspect its true for the trunk light as well. So when we tap for the hoodswitch between the trunk light and the trunk switch, it doesn't matter if we have a diode or not. Think about it.

orignal setup:

+
|
trunklight
|
securtymodule
|
trunkswitch
|
gnd

with the hood switch in the middle. w/ a diode:


+
|
trunklight
|
securitymodule
|
|----diode---hoodswitch--gnd
|
trunkswitch
|
gnd

If you had the diode pointing to the switch, it would work as if there was no diode there. If you pointed it the other way, it would work as if there was no switch there (like stock). A diode is useless because the hoodswitch isn't pushing current, its drawing it. To get this to work without trunklight coming on, you'd have to somehow position the switch between the positive source and the light.

I dunno if this is an exact representation of the order of items on the wire, but it does describe the behavior and what needs to be done.

jason

SF miami WRX

iTrader: (5)

thanks jason for the info.

farnsrocket

BACK FROM THE DEAD!!!!

I am a little confused on the placement of this diode. Is it connected to the trigger wire and then spliced into the blue and silver marked trunk wire on the module?
I got a diode at Radioshack......it is a 50v peak inverse voltage....is this good?

Thanks!