E46Fanatics - View Single Post - $5 Alternative for Lock beep
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Old 11-17-2012, 03:39 PM   #297
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Join Date: Jul 2009
Location: Columbus, Ohio
Posts: 1,025
My Ride: e46- 1999 323i
Originally Posted by USAF_BIMMER View Post
I'm gonna guess you went with a 1 amp SPDT Moro relay, because that's the only $5 pc relay they had, only question is how did you wire it into the buzzer and the connected for the alarm?
Mine was 10 amp I think? But 1 amp is probably enough I would think, I don't really know how much power those buzzers pull but probably not a lot.

To wire it, connect the SIREN wire (the one you had connected to the negative on your siren) to one end of the coil on the relay. The other end of the coil goes to constant 12V (the wire you had connected to your + on the siren). The + on the siren stays connected to that same wire. But now connect the - on your siren to the Normally Open wire on the relay (labeled NO usually) and the other end of the relay to ground. (There is a ground wire in the alarm bundle, I forget what color. Look at the WDS).

I'll try to find the exact part I used for the relay and write up a more explanatory/detailed explanation when I get a chance

Photo in Cleveland, Ohio
1999 323i - Totaled at 265,000 miles.
Now an e30 & e90 owner.
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