New challenge for Rando or others....

[ScottAW]

Rando recently came up with a way for us to modify our map lights to come on with the rest of our interior lights when the doors open, and I just thought of another challenge for him or others to come up with a solution for.

On my previous vehicle, as well as my wife's new Accord, there are LED's that are installed in the roof the car that point down towards the center armrest and stereo/HVAC console for lighting that area at night. It would be nice if the 4-Runners had that option too, because once you get used to having those LEDS, a vehicle without them just sucks.

So, since we already have power up near the maplights, I'm guessing we can probably purchase some LED's from radioshack and mount them up there - the trouble is powering them for only working when the parking/headlights are on. Or, we could just run them off the ignition power, which is already up there, and let them be on all the time.

Is there a special transformer needed, or can you purchase 12 volt LEDs that can be wired in paralllel with the map lights?

 

[rando]

Most LEDs have a fairly modest current demand so the map light circuit is probably capable of supplying the juice you need. You just need to add the appropriate current limiting resistor in series with the LED. Here's a handy calculator to help you select the right resistor. For a 8-14.4V source (remember, a cars power supply is not fixed), resistors in the 1-2K range are probably reasonable -- just depends on what your LED needs. Do your calculations with the higher voltage value to avoid damaging your LEDs. Here's another handy link.

http://www.kpsec.freeuk.com/components/led.htm

As for turning the LEDs on only with the parking / head lights, that shouldn't be a huge deal. You could always just tap the headlight circuit directly. That's bound to be a high current beast so there's seamingly no chance you'll install enough LEDs to have any impact on its proper operation. Other choices might be the the dash illumination circuitry that lights up the controls at night. You'd need to check how much juice is available on that one.

Don't expect any pictures from me on this one. With my map lights modded, I'm happy with my interior illumination now. I can't see cutting holes in my headliner to add a few LEDs. Post some pics if you try this.

AND AS ALWAYS, YOU PROCEED AT YOUR OWN RISK. YOU SHOULDN'T ATTEMPT ANYTHING IN THIS POST AS IT MAY VERY LIKELY RESULT IN DAMAGE TO YOU OR YOUR PROPERTY. I HAVE NOT TRIED ANY OF THIS AND HAVE NO IDEA IF IT WILL WORK.

 

[ScottAW]

Hmmm.... - Good info. I may have to give this a try.

FWIW, the LEDS in my wife's Accord are a perfect match color-wise.

Most LEDs have a fairly modest current demand so the map light circuit is probably capable of supplying the juice you need. You just need to add the appropriate current limiting resistor in series with the LED. Here's a handy calculator to help you select the right resistor. For a 8-14.4V source (remember, a cars power supply is not fixed), resistors in the 1-2K range are probably reasonable -- just depends on what your LED needs. Do your calculations with the higher voltage value to avoid damaging your LEDs. Here's another handy link.

http://www.kpsec.freeuk.com/components/led.htm

As for turning the LEDs on only with the parking / head lights, that shouldn't be a huge deal. You could always just tap the headlight circuit directly. That's bound to be a high current beast so there's seamingly no chance you'll install enough LEDs to have any impact on its proper operation. Other choices might be the the dash illumination circuitry that lights up the controls at night. You'd need to check how much juice is available on that one.

Don't expect any pictures from me on this one. With my map lights modded, I'm happy with my interior illumination now. I can't see cutting holes in my headliner to add a few LEDs. Post some pics if you try this.

AND AS ALWAYS, YOU PROCEED AT YOUR OWN RISK. YOU SHOULDN'T ATTEMPT ANYTHING IN THIS POST AS IT MAY VERY LIKELY RESULT IN DAMAGE TO YOU OR YOUR PROPERTY. I HAVE NOT TRIED ANY OF THIS AND HAVE NO IDEA IF IT WILL WORK.