So I'm wantinmg to wire in a couple underdash lights to the dome/map lights so that they come on when I open the doors. My problem is, is that I don't know where the best spot to tap into would be. I thought about using the wires running under my a-pillar, but there's four there and I'm not sure which ones are which and what/how I should tap into them. The wires are black, brown, white and orange, and the white and orange wires are a smaller gauge than the black and brown wires.
Oh and this is in an 03 Cavalier LS w/sunroof
Any help is appreciated.
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as far as colors, i couldn't tell ya. i don't have map lights, just the dome light. you can just get a test light and back probe the connector to find out what has power and when. then what i do it just use solderless crimp connectors. you can solder if you like. your choice. i haven't really taken the chance to look at it, but you MIGHT be able to tap into the switch at the door (the little thing that tells your lights when the door is open and when it's closed) for power. idk if that will work. never tried. good luck, hope i was somewhat helpful.
Somewhat =P
If I had a test light/voltmeter I would know already.. unfortunately, I don't. I thought about that switch in the door as well, but something tells me it's JUST a switch and I won't be able to get power from it, plus I can't really get to it. I might head across the street to the Advance my buddy works at and see if I can borrow their voltmeter... or I'll wait until I get more replies. It's getting a tad dark, the mosquitos are out in force, and I haven't even eaten yet =P
Thanks though =)
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If you pull the dome light cover off, get the wire at the light itself. There will be two going to the light bulb, just test them and see....But if I had to guess it would be the smaller wires, most likely the black one is (-)---DO NOT quote me on that though.
sam
Ban low-performance cars, not high-performance ones.
Green/Black wire off BCM.
Negative Trigger.
Use a relay.
-Seth
wizkiddrummer wrote:Green/Black wire off BCM.
Negative Trigger.
Use a relay.
-Seth
Mind explaining that in "amateur electricians" terms? =P
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Your BCM is the box under ur dash near the drivers side kick panel that controls the body electronics. Body Control Module.
If you look under your dash, ur gonna see it and 3 harnesses going to it. I would be able to give you the harness color and the pin number but I'm at work and don't have that info with me.
I would just use a crimp connector (or you can solder it, ur choice) and just run a lead off that Green/Black wire. Run it to the 86 pin of a SPDT (single pole double throw - has 5 pins) relay.
Run a positive 12V to the 85 pin.
Run a wire to your lights from the 30 pin.
Run a positive 12 v to the 87 pin.
Run a switched positive to the 87A pin.
What this will do is that when ur domelight turns on, the lights will turn on. When the door is closed, you can still turn the lights on by switching the power to on, on the switched positive wire going to the 87A pin.
I can draw u a diagram when I get off work.
Just ask if u need more help or if you don't know how a relay works because if you figure out how they work, it makes them a bunch easier to use.
-Seth
I think I remember you posting something like in a thread I asked about having it on the dome lights AND a switch. I've since then dropped the wanting of a switch and just want it on the dome light power lead. Would I still need a relay for that? Either way, yeah I'd like a little more info on it. Thanks =)
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Ya.
Just use a SPST relay then and don't put the switched power on there. Just a 12V on the 87. You might be able to get away without using a relay, but I would for safety.
K, relays in a simple way.
This is a SPDT and you have 5 pins. 30, 86, 85, 87, 87A.
On 30 you either have power - if you want to use the relay to switch between devices that get powered or you have the device - if you want to use different ways to power one device.
Now, when the relay isn't activated, you always have the current flowing from 30 to 87A. I just remember it by thinking "always" for the A.
On 85 and 86 you need a currrent to go across that and it energizes the coil (u can see in the pic). When that energizes, it pulls that "arm" across and connects it to 87. Then you have current going from 30 to 87.
That should help a little bit but just ask if you need more help.
-Seth
Ok so, just for clarification..
the green/black wire is what I need to tap into so the lights will come on when the doors open?
I need to buy a standard 5-pin relay and use it in the connection?
I have two lights, can I run both of those off the one relay?
What could "go wrong" if I just tapped into the power lead for the dome lights to power the under dash lights without using a relay?
Thanks for all the help =)
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1. Yep
2. If you don't want a switched power on, u can use a SPST 4 pin relay but ya, u can also use a 5 pin, it'll work just the same.
3. Ya, just make sure u have big enough wire or branch them both off the relay pin.
4. For one if you didn't use a relay, your ground from the lights would be the one that is connected to the green/black wire, not the power wire. Also, if you don't use a relay and the lights pull more amps then what is ok for that wire size, you would fry the wire.
-Seth
LoL get ready for a small electrical fire if you don't have a clue on how to use a relay
You know what, on my 04, the wire is white and when I looked on bulldogsecurity, it said the 03 was the green/black which sounds fishy but I guess if you find it we're good. If not, come back, lol.
-Seth
