Need some help here. I recently had a DVD drop-down monitor installed, and as a result lost the use of the dome light. There is a pair of lights in the monitor base, but the key has to be turned on in order to activate them. Kinda defeats the purpose of having some kind of automatic interior light come on when the door is first opened.

Anyway, I searched in this forum and downloaded a wiring diagram that indicates the "red/white" wire is the door trigger. So I'm figuring I'll buy some aftermarket interior lights and wire them into either the door jamb switches or this red/white wire.

So I'm in Auto Zone, and I see some packs of single LED lights, with two wires: red for power, and black for ground. I test the wires first on the battery, and they work as planned. Now, I'm taking the driver's door jamb switch out, disconnect the single wire from the back, and it's red, not red/white. Hmmmm, says I....

I figure the easiest way to get these LEDs to come on would be to wire them into the door jamb switch, and ground them to the switch bolt. So, I get out some test leads with alligator clips on the end, and proceed to test the wires. Well, low and behold, the LEDs work the OPPOSITE way: door open, light off; door closed, light on (this was done by pushing and releasing the door jamb switch).

So now I find the red/white wire that the diagram indicated is the door trigger, shave some plastic off to expose just the smallest section of wire, and try to test the LEDs again. Same result: push the door jamb switch in (door closed), and they come on; release the switch (door open), and they go off. WTF??

I tried reversing the wiring, putting one of the wires onto the red and the other onto the red/white, all with the undesired results.

What am I missing here? Why are the LEDs working in reverse, in that they come on when they door jamb switch is pressed, which happens when the door is CLOSED, and they go off when the switch is released, which happens when the door is OPENED?

Help!!!!

For direct replies, send to: rnd5962@aol.com

Thanks!!!!

 

use the red and white wire as a negative, prefereably with a relay, and find a constant 12v... to connect the leds too...

 

Think in reverse. Some lighting is triggered by a GROUND being the thing that goes on and off. Not a positive. The ground compleats the curcuit,--bassackward from what you'd normally expect. The ground is switching on/off not the positive.

As the previous poster mentioned. A relay is a good thing.

(EDIT: you could have some fairly freaky things going on with your DVD head unit, it's wired into a "always on" connection. If something is wrong on that, like a blackflow of current, it could make things behave strangely. The "door" switch on the dvd might be expecting to be switched from a positive--the Scion "door" switch is triggered by a negative. Plug in a diode there to prevent backflow.
Isolate, Isolate, Isolate. Relays for switching and Diodes to prevent current from flowing in the 'wrong' direction--if your DVD is leaking with a backflow; weirdness will be the result.
https://www.scionlife.com/forums/vie...ighlight=diode
https://www.scionlife.com/forums/vie...ghlight=diodes)

 

looks like your gonna need a relay to reverse the polarity..led's only work one way...light emitting diode...diode only lets current run in one direciton, the door trigger is a negative so, you need to wire the relay to reverse polarity when the door is open... throw a positive signal...my suggestion is to not use an led but to use a standard bulb that draws the same amperage as stock if wiring a relay is over your head.
jp

 

Thanks for the help. I'll try reversing the wires, putting the ground to the red/white, and the power to a constant 12v (red?) wire. I'm pretty sure I tried that combo already, with the same results.

Regarding not bothering with the LED, and using a standard bulb, I'm not sure I follow that line of thinking. A light is a light, isn't it?!

As you can tell, I'm not the sharpest tool in the shed when it comes to automotive electronics. But installing some additional interior lighting really shouldn't be this difficult, should it?!

Thanks again...

 

don't worry many, inexperienced installers get the door triggers confused as well...

 

Ok , here's the latest:

Red wire to door jamb switch on driver's door
Red/white wire on wiring diagram is for door trigger
Ground

I tried every combination I could think of using the above three wires, hooked up to the red and black wires on the LED light, and even threw in a switch for good measure. Nothing I did, either with the wiring combination, switch position, or door jamb position would make that darn thing act like a dome light.

So, I'm going to try one more thing. According to the wiring diagram, there is a white/blue wire that's supposed to be 12V (hot?). I'm going to try using that wire, along with the red/white and ground, and see if some combo of those three wires, connected to the LED, and a switch, will make the light work light a dome light.

If not, I'm going to wire them directly to the hot wire, and put a switch on the dash, next to the fog light switch, so I can manually turn them on and off, regardless of the door jamb switch.

 

you have two wires on your LED's...

there are many red and white wires in the kick/ above fuse holder etc...
to get the correct red and white wire... test the wire for the one that reads 0 volts when ANY door is open, and 12 v when the doors are closed, or the pinswitch is pushed down... when testing it on these cars it helps to have the doors locked as it will speed the process of the domelight delay ... make sure your windows are rolled down so you don't get locked out as well....

When you use the red wire are at the driver door, see if it goes to ground when any of the other doors are open...

connect the one that wire that needs 12v to a CONSTANT 12v source...
connect the one wire that needs a negative to the red and white...

 

oneslowxa -


Thanks for the tips. However, at this point, I'm about ready to throw in the towel. That wiring diagram I downloaded is giving me all kinds of fits. For example, it indicates there's a white/blue wire up at the ignition harness that is 12V. I scraped a little plastic off the wire, hooked up a test lead to the red wire on the LED, black wire to ground, and nothing. There's another wire, white/red, that says it goes to the horn. I tested the horn with the ignition off, and it works, so I'm thinking, "ok, this must be a hot wire". Nope, same results.

I hooked the LED up again to the red/white wire, which the diagram says is the door trigger, and it works, but the opposite way as I mentioned. When I put a switch in the mix, I can turn the LED on when the door is closed / ignition off, but as soon as the door opens, the light goes off and stays off. That doesn't help me at all, unless I just wanted the bling factor of being able to turn on the LEDs with the doors closed!

I just don't get it...

 

Uh... Maybe I'm the crazy one here but why don't you take your car back to the place that installed your monitor and make them fix your car so the dome light works. You are going through a lot of trouble for a problem that shouldn't exist in the first place but is the responsibility of the installer to correct. You didn't pay them to install something and break something else.

 

chadfo -

That thought crossed my mind. I took the DVD monitor off the ceiling, just to take a look at the wiring, and the stock wiring clip to the dome light was still there (I seem to remember a red/white wire and some other color). I couldn't get the built-in lights on the monitor base to work with the dome light wires, only with the switch in the monitor base and with the key turned on. The lights are no where near as bright as the original dome light, thus my crusade to install a few LEDs throughout the car.

I just might take the car back to the shop and run this by them. It's causing me a LOT of aggravation and frustration. Yeah, they need to come up with a good explanation as to why I can't get any interior lights to work off the door jamb switch.

 

One last try here. Can someone tell me what the color of the wire is that goes to the Hazard switch? That wire s/b hot, in that the Hazards can be activated without the key being on. I don't have any kind of test equipment, so I can't test the wires to see which one has current running thru it with the key off. Just knowing the color of the wire should be enough, and I'll try splicing into that wire with the LED power leads. That should give me LEDs that I can turn on and off all the time. Won't work in conjuction with the door jamb switch, but I can easily hit a button and turn them on manually if I need them.

 

Eureka, I've got some interior lights now! Taking the extremely low tech approach, I ran a wire from where the Hazard fuse goes for power, got a good ground, on/off switch, bullet and female spade connectors, and I'm cooking with gas now!

Once I had the bulbs all spliced together (one set on the driver's side, one on the passenger side), I tested them to make sure there would be enough juice to light them all up, and there is. They're actually pretty decent lights when there's absolutely nothing else on the inside. So I've got three single LEDs lighting up the driver's footwell, and four on the front passenger side. I bought 6 single red LEDs, and I'm going to put those in that plastic post that goes from under the front seat belts down to the floor. Space them about 4"-6" apart, and angle them so they shine towards the rear seats. Run the wires along the bottom of the door channels, and plumb them into another switch that I have right next to the one that activates the front interior lights.

It may not be the best solution, but for a low tech guy like me, they work! And these LEDs are so small you really won't notice them, unless you look real hard!

Thanks for all the advice...