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.

Thanks goes to mmboost for this mod:

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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