Ive got a GE with the JDM mirror covers. Mine are aftermarket, and include blue leds in addition to the orange winkers. My goal with these blue leds is to have them come on with the dome/courtesy light when i unlock my car. OR at the very least have them flash with my parking lights when i unlock the car. the only problem with the latter is i believe that would cause the blue leds to stay on with my headlights... which is illegal since they are blue.

sooo, that leaves me with the option of only being able to connect to my dome lights. the problem here is: the dome lights are controlled by ground, and use constant power. the way my blue led is wired up, (its ground is tied with the orange winker, which is bolted to my frame) if i were to just connect the + of the blue led to the dome + it would just stay on constantly. If i connect the blue LED+ to the dome -, it would do the opposite of the dome light.

My question is: Is there some way of getting my blue LED to work in sync with the dome? right now its doing the opposite.. I figure there must be some kind of component or IC that can output + to my Blue LED whenever the dome - is activated.

thanks for any help,

Connor

 

You can use a relay to swap the polarity. Here is a link to the page on the12volt.com : Relays Diagrams, Converting Polarity

This should get you to where you want. You should also be able to tie into the dome light circuit at the door switch in the jamb.

 

Nice! thats exactly what i was looking for. Thanks!

im not a huge electronics expert..so for the dome light constant
12V, i would need to split it into 2 leads for inputs 30 and 86 in the diagram. Dome negative is 85. LED + is 87?



am i understanding this correctly? can i just directly connect the applicable wires to the relay, or do i need resistors/diodes/etc?

thanks again!

 

Never mind, I jut called the local active electronics.

Apparently if my domes are dimming, the relay will short out because it's only meant to handle on(12v) or off signals.

 

I would see if your door trigger (at the door pin in the pillar) decays off or stays 12v (give or take a few tenths of a volt) until the light dims. Sometimes the signal side (from the door pin) feeds the BCM and it takes care of dimming.

 

Sorry, but i only partially understood your answer. Im a little confused in some areas.

Can you explain in more detail where i can find this door pin? ( and more specifically the door trigger)

IM not sure what the BCM is, but it sounds like youre saying this is the component that controls the dimming of the dome light, and the original signal (which is coming from the door trigger?) is a simple on/off. If this were the case, i could connect the relay to the door pin/trigger.

am i on the right track?


Thanks again for your help!

 

Sorry about that. The door pin (or the door trigger) is in the b post (which is between the front and back doors where the front door shuts and the rear door hinges are) and is a small black rubber boot. The BCM is the Body Control Module and is generally in the front of the cabin inside the dash on the floor. The BCM interprets the signals from the car and does what it needs with them. In the old days all of the door triggers were a common signal and you got a generic light on the dash that showed door ajar. Fast forward a few years and cars now tell you which specific door is open. The BCM receives the signal from the respective door and interprets that and sends out two signals. One goes to the dome light and tells it to come on. The second goes to the instrument cluster to tell which specific door light to come on.

I am not 100% sure since I've never wanted to do something like you want but I would expect the signal to the BCM to be a full 12v with the door open and the BCM takes care of dimming. After re-reading your original post again I'm not sure that you can get what you want since you want the lights to come on with the disarming of the alarm (which would require you to tap into the dome light signal). My way would only get you lights once the drivers door is opened.

 

I see, what if I found my alarm module and connect the LEDs to the unlock wire? That way it would still come on when I use my unlock remote, and it would probably be a positively controlled signal.

Would you know where this is located in the fit?

 

For my post above, which of these wires should i plug into in these diagrams?

Vehicle wiring diagrams

2011 honda fit alarm wiring needed

im thinking to connect to either the power unlock or lock(probably unlock would make the most sense here), but it seems like its also a - polarity so i guess the relay would work here...

 

The door trigger and the dome light wires are blue (-) but they both indicate to tap into the circuit at the BCM. I would physically pull out the door pin and see what you have there. There should only be one wire (since it grounds itself when it is screwed to the body) and it may do all that you need.

The door unlock may work but without using a diode and possibly a cap it will only flash since the signal is only a pulse. If you are okay with the flash (like you said in the original post) you could tap into the parking light wire. I would pull the the door pin and see what it meters at, since it might give you what you wanted in the first place.

 

Oh for the unlock I thought it may have been a constant signal because it locks if you don't open the doors within 30 seconds. I'll check this out when I have some time. I have the LEDs temporarily connected to my oem Ambient lights. They flash with my parking lights, and I can manually switch them off at night if there are cops around.

 

So i was rethinking what you originally suggested. Would a PNP Transistor work in this situation(in place of the relay)? Forgive my rusty electronics knowledge, but cant this type of transistor be triggered by a variable ground as the input? That way , i could connect the base of the transistor to the dome negative, and connect the LED to the Transistor collector, and transistor emittor is tied to 12v constant.

Think this could work?

Thanks again for your patience in helping me along... im sure ill get something to work eventually.

 

Unfortunately I don't have alot of transistor knowledge. I would think it would work, and it may be your best option. My only question would be that PNP is designed for closer to 0v but that is still something that may or may not work. I guess it would come down to which ever one is cheaper since they seem to do about the same thing, just differently. The only thing that I think may be an issue against it would be the limited current capacity of a transistor.