Challenge for the electrical guru's
 

Alright so i had a good idea today. Wouldn't it be nice if the headlights went on along with the dome light when you unlock your car? Make it easier to spot in a parking lot, and allow you an easy way to see around a dark garage (kinda like leaving lights on, but when the dome light turns off, so do headlights)

The only issue I found with this is keeping the headlights independant of the actual switch for the dome light. Possibly the relay that activates the dome light upon unlock could be spliced to the headlights. If anyone here has any more experience with this type of stuff blurt it out! I guess i'll start doing this over the weekend either way.

dads impala has that feature

Wouldn't it be better if the parking lights turned on instead of the headlights? That way you wouldn't blow out your headlights locking and unlocking you car every time.

quick idea, i havent put much thought into it but i think it would work

relay:
85 ground
86 12v from dome light
87 12v positive constant
87a headlight turn on
30 headlight bulb

you'll need to run signal relays to make this work. it's not hard at all. the only problem is, if your headlights are on by the signal relay from the dome light, and you turn on the headlight switch manually as if you are turning on the headlights at night before driving, you'll get an overflow of currents back into the signal relay or the headlight relay. you'll fry up one of the relays for sure. in this case, install a low emission 1-way transistor onto one of the relay's power suppley to the headlight. you'll lose some voltage across that transistor, but will ensure both relays work fine, but then headlight wouldn't be so bright by one of the relay's so preferably set the transistor on the relay activated by dome. yeah, that's it.

that makes no sence a relay switches between 2 sources and will not "add" them together.

if both relay's are running power into one device, turning both on will reverse polarity or overflow currents. they don't add, they actually overrun one or the other depending on the circuitry.

I've burned a few relays running passive relays for my blue led interior light setup. both the parking light switch and dome switch activate my blue led interior lights. but on has more voltage than the other, so running an led on the dome activated relay solved this problem.

to further clarify what i'm talking about, there aren't two sources running into one relay. I'm talking about 2 relays for different sources of activation, but both relays activate power to turn on the same device. If both relays are turned on, then one of them better be "one-way" preferred so it won't burn the circuit.

you dont need 2 relays.

Ok so i understand i need a relay, obviously 12v, but what other specifications should i be looking for? and also, would i want to buy this at radio shack or autozone? thanks so far, ive really got no clue about relays besides for their function. Thanks again!

i bought 10 on ebay with harness' for cheap. locally the crappy ones go for about $4 each. those dont have the 87a terminal either. you are best off with bosch but any 5 pin 30 amp relay will work.

How about just getting one of those LED dome lights, the kind that's in the 4th gen classified. It'll be so bright I'm sure you'll be able to see your car from a distance anyway. And if visibility from a distance is what you are really after, then just hit the ARM button on your remote and the blinkers will blink letting you spot your car. Do it repeatedly until you find your car. Voila! Having too many relays in any circuit just adds more areas where things can go wrong and cause problems in the future. I tend to leave stuff like that alone on any car except for the audio system. :)

Yeah i debated that, but this is just something that I want to do. I'm sure it'll have more uses in the future, but for now, i can use it for temporary lighting, easy spotting, and it gives me something to do for a relatively low cost that might pay off in the future. Hunt for a relay begins now!

Edit: What I just thought about, is there must be a relay that turns on the dome light with unlock (or is it the BCM?) Would it be possible to just use that same relay to activate the headlights, or would that cause an overload? Just brainstorming here

i wouldnt hook the headlights directly off that wire. it could cause all sorts of problems.

Alright i took your advice, went out and got a 5 pin with 85 86 87 87a and 30 terminals, didnt get a harness though, is it really necessary? Either way, im studying the wiring diagrams right now and it all looks sound. I'm going to wait for it to warm up to maybe 25 to start on this, but once again thanks for the info! keep it coming.

you can use regular disconnects insted of the harness.
http://www.crowbarelectricalparts.co...-connector.gif

Thanks. I'll do a writeup while im at it, just in case anyone else out there sees the need for this. Stay tuned!

I was going to do this, but with fog lights, I didn't want to take the risk with the head lights, also if you wire it to the dome light, they will turn on every time you turn on the light, or open the door along with unlocking.

You need to activate your relay from the signal from the BCM that turns on the light. So they will also turn off after the 30 or so seconds that your dome light turns off.

I just haven't had the time to open my dash and start testing wires.

The Chevy Tahoe/GMC Yukon has this feature, but it turns on the daytime running lights & the back-up lights. I didn't get this feature until I was camping and it was pitch black when I unlocked the doors and viola I can see the path to and from the car in both directions.

That's the idea, I guess i didnt convey it well enough already :)

Sorry i dont have a direct answer but i think you can buy a activation input module from D.E.I. that will run a negative trigger for 30 seconds (cant remember if you can program it for different times) or so when it receives two (-) triggers. You can use this to activate the headlights when you hit the lock button twice on your remote. And then it shuts down when it senses a 12v input, from a brake pedal or anything.

Does anyone else recall if d.e.i. does sell this im not 100% on it

Alright Update time. Today was amazing weather, so i went out and tore my interior apart looking for wires. I've found that the dome light is on 2 circuits, the one activated by the BCM, and an independent one (the physical switch on the light). The wire that goes from BCM to dome light is red/white. Thats where my ingenuity ends. Ive hit a wall, and have NO clue where to go from here.

If you have an electrical tester, check that wire, for voltage, it should be zero, the press your unlock button, if it now has 12V, thats what you need. Use that wire to power a DPDT (double pole, double throw) relay and use it to switch on your headlights or fog lights. I suggest fogs so you don't mess with your headlights.

I think I'll do this, and I'll make a write-up.

Also check it with the doors open and then closed. To make sure that is actually from the bcm and it isn't also powered by the door switches.

yeah thats what i did all that day. i disconnected everything individually, because i dont have a multimiter atm, so i did what i could without continuity testing.

just a thought, doesn't the panic button do that?? i mean, i know it makes the lheadlights go on n off to the sound of the horn. so maybe you should try looking into how the relay works once the panic button hits. you can use diodes instead, maybe that will help


i apologize for my sig, dunno why it was posted, it usually isn't

please make sure you use THICK wire Atleast 12 gauge headlights run alot of current. Also make sure you have a good ground for the relays.

I have done quite a bit with my headlights and know a lot about electronics (especially wiring and relays). You will need 2 relays because each headlight is on it's own circuit. I would suggest using the key ring light to trigger the relay. It comes on when you unlock the doors, goes off in 30 seconds, is right by where you need to do the work, goes off when you lock the doors so they will stay lit when your walking away.


http://forums.maxima.org/showthread....eam+horn+write
You might want to check this link out. It is where I made my high beams come on when the horn is honked. It is pretty much the same thing that will need to be done here only instead of the power going to the high beams, it will go to the low beams and you will be using a different source to trigger the relay. I don't remember which wires are the low beams, but I will look for my drawings if you want. It a while to find out which wire did what because all the wiring manuals for the Maxima were wrong about the colors.

BTW you will not need 12 gauge wire. 16 is plenty big enough for the headlights.

RockfordMax,

I think most have covered how they think you should approach this issue. I tend to believe that your method of using the signal off the BCM is the best way to go about this. Reason being, the key ring light, the dome light and other accessories come on when the lights are on, while the BCM signal is just active for that 30 seconds or so. ALSO, I would recommend possibly hooking this up to your fog lights rather than the head lights, as both foglights are off the same relay. With that said, you could basically run the signal from the BCM into your new relay which you can then tie into the relay for the foglamps, in parallel with the existing wiring. Once the BCM has done its 30seconds thing you don't have to worry about your newly added relay.

Hope it all works out for you.

What do you mean the key ring light comes on when the lights are on? It comes on when you press the unlock button on your keyless entry and stays on for 30 seconds or until you turn your car on. It also goes off if you decided to just lock the doors and not get in.


I would recommend going this route too. It actually wouldn't be to much easier though, because you would have to use another power source to run to the fogs. This is unless you have your fogs set up completely independent of your parking and headlights. If you wanted to still do it with the regular headlights, the power for them is right there at the steering column.

Here is the picture of the fog wires/connecter in the dash.
It is the white plug circled on the left.
http://memimage.cardomain.net/member...03_22_full.jpg

Thanks a ton for that burst of info guys, today i got a bit more wiring experience putting in some air horns :woowoo: , I ended up going through all the trouble of wiring in a new relay, when i didnt even stop to think that the stock horns ran off of one anyway (durhh), but now i'm at least COMFORTABLE with relays. I think tomorrow i'll get working on this, temperature permitting. Once again, thanks a TON for the help (pics and otherwise.) i'll credit you all when I do the write-up! :)

Best of luck on it...keep in mind its best to go off the BCM and not the key ring. The key ring lights up when you take the key out off the ignition, and you wouldn't want your lights on at that time.

Keep us informed.

I could be wrong but the switch wire for the actual slide switch should be independent from the wire that turns the dome light on when the car is unlocked. You would need to put a diodes (if it is a positive) on the wire from the switch and from the "turn on signal" to the turn on to the relay you hooked up which in turn activates the parking lights/headlights.

Sounds good, but the reason they give you a relay is so you run a wire from the battery with the in-line fuse they give you. When I put in air horns I avoided the relay at first, but then blew the horn fuse and was forced to learn a little about relays. I got addicted to them and bought a bunch off Ebay and just started using them everywhere.

The relay should be hooked up like this:
Pin 30 = Wire from battery with in-line fuse they provided
Pin 85 = Wire that triggers horn (old horn wire)
Pin 86 = Ground
Pin 87 = Power wire to air horns

BTW did you ever find out what those wire taps by your fuse box were for?

You're correct. I thought he wanted it to be on when he leaves the vehicle as well. That's how most of the cars that have the lights come on via the keyless entry are set up. If he doesn't want to have them on when he walks away from his car, then he should use the BCM.

Well with the air horns, I noticed that the inline fuse was 20A, and the normal horn fuse was something like 10, so when that blew, i just figured, well what difference does it make here or there, so i threw a 20A fuse in the slot, has worked fine since. No wires melted or anything else shady. About to go to work on the headlights, ill report in in a bit.

You should probably be ok. Right now I have a 15amp fuse in there. I made a contraption that uses one of those air horns from boats and that some people take to sporting events. My electric air horns just weren't loud enough and there was a little delay. It is set up using a trunk solenoid that needed 15amps.