i wanted to post this in the diy forum but it wouldn't let me post there (no idea why). there's a thread in the diy forum showing how to wire the detector to the map lights, but if you do it that way then your detector will always be on, even with the ignition off. if you do it my way, it'll only turn on with the ignition.
this was done on my 08 si coupe, it's possible it could be a different prong on 4 doors and/or different years.
i have a valentine 1, the only extra things i needed to buy were the 2 connectors for the ends of the wire (1 of each), zip ties, and double sided tape (optional). the connectors that were on there originally were the wrong size.
click on the pics to see them full size.
i tucked the wire into the headliner and ran it down behind the pillar cover. i ziptied the wire to the wiring that was already there. the pillar cover is held in with plastic clips, to get it out use a flat head screwdriver and start prying at the top. to remove the bottom cover that's over the fusebox just tug on it starting at the bottom.
i peeled away the rubber molding in the door jamb, which exposed a perfect spot to run the wire through from the pillar to the fuse box.
this is what i connected the red wire to. in the box in the top left corner of the fuse box, i used the top right prong. using that spot the detector will only turn on with the ignition.
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this is one of the connectors that i had to change. the original one was too big to fit into the spot in the fuse box. i forgot to take a pic of the connector i used for the black wire but it's the same shape as the original one, just bigger. original one was too small to fit the bolt through.
i connected the black wire to the bolt holding the fuse box. gotta take the bolt out first.
this is where i put the relay that comes with the detector and the extra wiring. the zip tie on the left is holding the relay, zip tie on the right is holding the extra wiring. i first used 3 zipties to clump the wiring together before attaching it to the dash. i put some double-sided rubber tape in between the relay and dash to prevent rattling.
the finished product
