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Alarms & Installing Them

If you have no interest in alarms, you can ignore this long post.  If you
are planning on purchasing one, you should probably read through at least
the first part of  this whether you intend to install it yourself or not.

Richard, could you add this to the FAQ please.

That said, guess what I did all weekend recently!  I thought I'd relate
some of my install experiences to the list so that everyone will have a
sense of what's involved in order to be better able to determine whether to
go w/ the BMW/Alpine unit or an aftermarket brand and whether to tackle the
install themselves or let a pro do it.

Aftermarket vs. BMW alarm in hindsight:
- --------------------------------------
- - There was no starter kill on the connector on my car.  According the '94
BMW accessory catalog, this feature was added for 1994 and later models.
This is probably the best reason I've found not to go w/ the BMW unit,
assuming the car is a '93 or less.  W/o this, defeating the alarm is as
simple as cutting the siren wire under the hood. (See tip below on hood
lock.)

- - Warranty issue.   Anytime you add _any_ type of aftermarket accessory
there is always the chance that it could effect a warranty claim.

- - Install ease.  Assuming the aftermarket alarm has decent instructions and
no additional features, with the information below, it should not be much
more difficult to install an aftermarket alarm compared to the BMW unit.

- - Features.  One interesting revelation was that a hood lock and backup
battery backup could be added as easily to the BMW unit as to my Alpine
once the connections were figured out.  No way to add more sophisticated
features like a motion sensor, tracking, anti-carjacking, etc...

- - Ease of defeat.  Knowing what I do now, defeating the BMW alarm, or a
similar unit wired in the same way, hot wiring the car, and driving away
would be real easy and real fast.  More sophisticated features would make
it take longer, could leave the siren running longer, and would make it a
more risky proposition for a knowledgeable thief.

Tips:
- ----
- - For a cheap hood "lock" remove the handle that opens the hood.  On mine
at least, it is a one screw affair and will work fine by just slipping it
back on w/o the screw.  This way you can keep it hidden away in the car. It
won't stop a determined, well equipped thief, but it will prevent them from
being able to quickly silence the siren by popping the hood and cutting the
wire.

- - Hide the siren and its wiring as well as you can. I mounted mine just
below the headlights. (wasn't easy.)

- - When working with the starer wire (pre '94), be sure to remove that large
aluminum  "knee guard" thing under the steering column.  Getting to the
wires is a breeze w/ it off.

- - Mount microphones, LED's, etc... in blank switch plates.

- - I hid my valet pin switch under the shift boot.

The Anti-theft connector:
- ------------------------

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
x                                         x
x     1     2     3     4     5     6       x
x                                          <x
x    12    11    10     9     8     7       x
x                                         x
 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Pin #       Function
- -----       --------
 1          Domelights ****
 2          Trunk sensor (negative type)
 3          Central Locking System, Unlock (+12V triggers)
 4          Central Locking System, Lock (+12V triggers)
 5          Hazard Lights (negative trigger)
 6          Siren Connection
 7          +12V Constant (Battery)
 8          +12V Switched Through Ignition
 9          Ground
10          Passenger Door Sensor (negative type)***
11          Driver's Door Sensor (negative type)***
12          Empty on my '93 318is

            Hood switch (if available) is violet/green/yellow.****


** - On E36 cars at least, the BMW siren is mounted in plain sight, between
the strut tower and the firewall on the passenger side. The empty plug for
the siren connection is right there also.  Test between this pin and the
connector to see for sure.  One should be ground and one to this pin.

*** - Do not connect pins 10 and 11 together to the same alarm input on
models where the windows lower and raise automatically when opening the
doors.  If connected, both windows will operate when opening only one door.
Guess how I figured this one out!

**** - Information provided by ARMAND_A._AQUINO.Henr801B@domain.elided

Note there was no starter/fuel system kill connection.  This is the case w/
pre '94 models.  If you have a '94 or later you could locate the factory
connection or do it this way if you cant figure out the factory wiring. I
you have a pre '93 you'll have to do it this way:

The starter wire is underneath the steering column. On my car it is black
w/ a yellow stripe (14-16 gauge), goes through a connector identical to the
Anti theft connector, and is next to a red and green wire of the same
gauge.  You will need to cut this and run it through a relay connected to
the starter kill on your alarm.

If anyone has any more detailed questions, feel free to mail me.


Jimmy Shrake
Current: '93 318is
Previous: '85 325e (KIA @ 150k)

jim@domain.elided