Linking headlights to interior light
 

Just a thought I had.

How easy would it be to wire the headlights to come on when the interior light comes on? A lot of modern cars now have headlights that turn on when you unlock the car, but also when you open the door at night. If the headlights were linked to the interior light, it would give the same effect.

Obviously I'd still like to turn them on as normal, but I just want the courtesy light to turn them on too.

Hard to do?

I imaging with a few relays and the wiring diagram you could .

Might be easier for you to move the steering wheel to the correct side (left):D:cheers:

Well, it was kind of a question towards people who would possibly know how to do it haha.

And I'll keep the steering wheel on the right side thanks very much! (Right in both senses of the word :D)

that is very interesting mode.
it should be fairly easy to achieve with 1 relay connected at the back of the fuse/relay box.
the only challenge is to locate the correct wires, but they both should be there.
what year is your box?
maybe i can have a look at the diagram for you.

It's a 2003 facelift Boxster S.

Thank you :) I think it'll be a nice modification. Because modern cars have a feature at night when you open the door the headlights come on, or when you unlock the car it'll come on, etc. Just linking it to come on with the interior light will be all that's needed to do it :)

Yes I totally get it.
I might even do it on my 02 996. Should be same electrical system.
What did you had in mind? Activate the parking lights, or the main?

This should be fairly easy.

The headlights are powered from a relay that is activated by the switch. All you have to do is activate the relay. One way to do this would be to tap into one of the wires powering the interior lights and run it to the correct pins on the headlight relay. Thus, when the interior lights turn on, the headlight relay will be switched on and then the highlights should turn on.

This is very similar to the hack that I posted to control the engine compartment fan using a manual switch (http://986forum.com/forums/diy-project-guides/60239-engine-compartment-fan-manual-switch.html).

What I'd have to check is what type of relay the headlights use (standard Type 53 or something else) to figure out which pins to jumper and if the 2003 S is wired close to the same as the 97-99 base that I have - but the principle should be the same even if the exact details are different.

But your wife will notice when you sneak out at night and that is a big no, or is int?

None.

A switch and some fuses is all (this is why our switches are so prone to failure).

I know there's a hack to turn the fog lights on with the car by using a jumper between fuses. Maybe a similar approach?

I would have thought if there's anyone here that could do it, it would have been you :D any idea on how this could be done?

Pwave is right.
I spent couple of hours last night, going over the diagrams looking for the headlights relay that doesn't exist :(
But just
I will post some diagram later on how I think it should be done, but basically you need to use a relay to jumper between the red and white/black wires, at the light switch.
Both are heavy gauge, so you will need a 30/40 amp relay.
The relay will be activated by the brown/yellow wire that comes from the BCM.
Since it is running all over the car, it can probebly be located at the ckick panel/ fuse box area. Same goes for the wire that comes from the light switch. It goes into the fuse box, and comes on the other side as yellow/black.
Obviusely you need to connect before the fuse.

Thank you :)

My only concern is that I use HID's, and the courtesy light uses a dimming feature to turn itself off. I wonder how that would affect the HID's - I'm hoping they'd just turn off once the voltage goes under a certain amount.

well, the courtesy light will not be connected to the low beam circuit.
it will activate a relay that will switch the lights on and off.
so when the courtesy light will dim out to a certain level (in voltage), the relay will interrupt the lights circuit instantly.
the relay i tested disconnects/reconnects at 3-5 volts range.
here is a quick video i made.
https://youtu.be/mOkvLh2l1fw
pay attantion to the clicking noise coming from the relay, once the lights dimm out at around 3-5 volts
ignor the first click sound that is coming from the power supply.

Just a related thought:

A 55w headlight draws about 4.5 amps each so without a relay, upgrading to a higher watt headlight bulb as some folks do will also shorten the life of the light switch (as well as burning the plastic lens).

You will need to put in a 10amp+ relay for the headlights that will now trigger from the light switch AND the courtesy light signal wire?

Wondering if the current will flow the wrong way and damage something if the signals are not isolated from each other?
Perhaps a couple diodes will prevent that possibility?

it will be no problem.
the added relay will act as the switch itself. no need to isolate anything, as the relay will imitate the switch.
you are right about the load though, that is way the switch is so robust and more have duty (compared to other cars that uses a light relay)and uses thicker wires. not that it really helps as mentioned by Pwave.
i have to admit i was surprize to find out that the light system do not incorporate a relay.
circuit diagram to follow in a bit.

the diagram for the light system is scattered over few pages, so i had to build a small puzzle. i also apologize for the low quality pictures taken with my cellphone.

first, this is where you can see the main power line (red wire) going into the switch.

http://986forum.com/forums/uploads02...1478729015.jpg

if you follow the line to another page, you can see it goes to the current distributor.

http://986forum.com/forums/uploads02...1478729097.jpg

the current distributor is basically a junction box from the battery positive lead, backed up by 80 amp fuses. it's located behind the ac air box.

now, this is the line that comes out of the switch (white/black), splits in two, goes to the fuse box, and on the other end, change colors and go to each individual head light.


http://986forum.com/forums/uploads02...1478729612.jpg

on the other side of the fuse box the colors changes to yellow/black for the left headlight, and yellow for the right.

http://986forum.com/forums/uploads02...1478729674.jpg

and here is the relay diagram.
obviously, the easy way is to locate the relay next to the light switch, and run a wire to the A pillar/cick panal to get to the courtesy light wire.
i will try and have a look this weekend and see where the best place to connect.


http://986forum.com/forums/uploads02...1478732988.jpg

This is looking VERY promising! Be sure to write a guide! :D

If your courtesy lights dim out, you'd need a controller circuit to power the relay. Otherwise, the relay would chatter as the voltage drops to near the relay solenoids threshold. This would cause premature failure of said relay and wreak havoc on the HID ballasts and bulbs.
You'd need a micro controller that applies/cuts power to the relay at a predetermined threshold.

Even with the controller, they'd want to come on and off a lot and would not be good for the HIDs. Incandescent fog or parking lights would be better.

Advise taken.
On the bench the relay acted fine when I simulated the voltage drop, but I will test it on the actual wire in the car.
Agree on the fog/parking lights instead of abusing the litronics (in my case).

Whaaat? There's no headlight relay? :eek:

I thought there had to be one, but didn't have time to check the wiring diagrams.

Sorry for the misdirection and thanks for the correction.

Any news on the testing side? :)

Didn't get a chance to look at it this past weekend.
Hopefully later this week, as I have to do some other electrical projects on the car.
I already have an OEM relay holder, and just got these today
https://www.amazon.com/gp/product/B01G7KKBYG/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
So I can replace the wires with thicker ones.
Also have this on the way
https://www.amazon.com/gp/product/B00ZYXHR6S/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
To remove the existing pins from the relay holder.
The idea is to use the correct wire gauge and locate the relay on the relay carrier above the fuse box.

so i spend some time today going over the diagrams, and looking at the fog light circuit.
it looks like the lights should be isolated from the switch before power is directed to them. otherwise, the light switch will be probably damage.
not a big problem, will just have to use a 5 legs relay.
i also tested the wire that comes from the BCM, and basically going to trigger the relay.
wanted to confirm that the relay will not chatter when the power gradually drops, and the lights are dimming out.
i made a short video of the process.
https://youtu.be/jPfQFOOu45c
after filming the video, i thought it will be a good idea to add a timer to the setup, so i will be able to control the length of the "On time" after locking the car.
so i will probably get something like that, and also use it as the relay.

http://986forum.com/forums/uploads02...1479700648.jpg

might even go pro and add a Photoelectric Switch :dance:
Zing Ear SNR100A Photo-Electric-Resistor-Cell Light Detector Sensor Switch 25W | eBay

just because i don't like threads that don't end ;)
i just got today the parts i order from fleebay (under a month from china is not bad).

http://986forum.com/forums/uploads02...1481578801.jpg

the big board is the timer, that has a NO/NC 30Amp relay.
so i can connect it directly to the fog light wires.
the small board is the photoelectric sensor that will control the timer.
so basically it is going to be connected to the interior lights, and will trigger the timer only when it's dark. the lights will stay on (after i lock the car) for 10 seconds or any other settings i will put in the timer.

so before i start i want to modify the components, and check the power consumption.
if it will be within reasonable values, i will install it.
will keep you posted when i make any progress.

Well that's complicated lol!

I just wanted them to come on and off with the courtesy light lol. Going back to the original question, would that be easy to do? Rather than adding timers and photoelectric sensors? Literally just want the headlights (or parking lights) to mimic the courtesy lights.

Going back to basics: would a 12v feed with a diode from the courtesy lights to the side lights work? So that when the courtesy light turns on, the sidelights turn on, but when the sidelights are manually turned on, it doesn't turn the courtesy lights on.

If that works, that's literally all I originally wanted :p the only thing I'd need to know is the wattage of the diode. It would be a 12v diode, but what wattage?

Unfortunately, it's not that simple due to the side lights being positive voltage actuated and the courtesy lights being negative ground actuated. The circuit I posted won't work, either. You're not going to find a diode big enough. I was rushing. :o
You would need to use microcontrollers and relays like Meir is doing.

Totally forgot about that relay! That's what I'll have to do :)

But I'll admit, got quite confused by how you work out the wattage. So, would it be 12v multiply by the amps of the sidelight fuse? :/

See my edit. It won't work because you're not going to find a diode big enough. It's late here and my brain is shutting down, lol :)

Damn it. So there's literally no quick way of doing it?

LOL!
no the whole timer and light sensor is my flavor for the idea that you got (and i like).
but you will need a 30 amp (at minimum) relay. two if you want to connect to the runing lights.
when i get to it, i'm going to connect to the fog lights, but will show also the connection to the running light.
just one clarification needed. when you say corner lights, are you referring to the parking lights?

just so we all use the same terms.

http://986forum.com/forums/uploads02...1481669371.jpg

so witch one you were thinking to link?

Parking lights with courtesy lights. When the courtesy lights come on, I wanted the parking lights come on too, so that your tail lights, number plate lights and front parking lights illuminate. But I wouldn't want the switch to turn on the courtesy lights if I switch it to the parking lights position, if you see what I mean. So a diode would be needed.

I just thought "Oh! I'll just bridge the 12v from the courtesy light feed to the parking light feed with a diode, so the parking lights don't switch on the courtesy lights, but the courtesy lights do turn on the parking lights whenever the courtesy light is on". But as particlewave said, the courtesy lights have a switched ground, whereas the parking lights have a switched positive. If they were both the same, it would be that easy.

I thought about jumping the fuses but, there's a separate fuse for each bloody bulb. So that wouldn't work either.

Ger.

I believe you have your new DRL's wired to your parking lights. Having them come on with the courtesy light would be great but have you got a hack where they come on automatically with the ignition?
Seems there is a hack for the foglights to come on as automatic DRL's but could do with a hack for parking / sidelights to come on in this instance.

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Probably going to do that anyway with the DRL's, but that's not a massive bother for me. It's having them come on when I unlock the car, that's what I'd love. The DRL's are very powerful and light up the road quite well, so they'd also serve a purpose when walking back to the car in the night.

Anyway - It's a good project that you're doing with the photometric sensor and all, and I'd be keen to see it work, but for now and for the purpose of the original question and the reason for the thread - is there any way to just simply wire up the parking lights to the courtesy lights?

Even with the use of a 5 pin relay, for example? That's literally all I'd want at the moment - I didn't expect this to get carried away into photometric sensors that leave lights on for 10 seconds after the car is turned off etc etc. Like I said, I massively appreciate it and it sounds amazing (and be sure to show us when you're done), but I'm just interested in turning the parking lights on when the courtesy lights come on.

So is there a way to do this with a simple bit of wiring and relays? This is me talking off the top of my head and probably absolute rubbish, but could the courtesy light's ground wire be wired into a relay, that when given a current, tells the relay to send power to one of its pins, which is the 12v feed for the sidelights? That may not make sense, but it's something like that which I'm thinking of.

Is that not possible?

Yes, I realised that. Can they be tripped on by anything to do with the central locking?

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Had an idea (post I just made above), but if the car's unlocked, the courtesy light can turn off to save the car's battery. If you wire them up to the central locking, the lights would permanently stay on for as long as the car is unlocked, which wouldn't be good.

Just trying to figure out if there's a way to wire a relay so that if one pin gets a current (in this case, the courtesy light's ground), then it can switch on another one of its pins (a 12v feed to the sidelights). That's all I'm after, a way to wire that up. It probably sounds easier than to actually do it and it may not be possible, but that's why I started the thread :) as good as it is, I'm not really after any special light sensors and timers. Just a way to make this work.

I see that there are relays with timers built in. Would this work

http://www.12voltplanet.co.uk/12v-universal-interior-light-delay-timer-relay-10-sec-delay.html


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