Parallel Wiring of LED

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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=37645
Printed Date: May 13, 2025 at 11:49 AM

Topic: Parallel Wiring of LED

Posted By: terrynham
Subject: Parallel Wiring of LED
Date Posted: August 18, 2004 at 3:20 AM

Hi, im new here. Ive done a search and found a few topics relating to my topic, but it didnt help too much.....:errr:

any how, this is my problem. I have a 1994 Toyota Camry. and I have decided to do a White LED conversion to all the interior lights.
it was going fine until I accidentally short circuited the Rear Demister Switch.....this burnt out the Switch and damaged the LED.....
I bought a replacement switch from a junkyard, and it works fine....BUT however, when i put an LED in there, it would burn out after about 30mins of being on.....however, using a normal bulb it doesnt burn out......
this is confusing as I have also done the same LED change to my A/C Switch and that has been working fine for the past few days......;), and so has every other LED i have put in......

So i assume I must have damaged something else along the line which is causing this burn out.......
so instead of powering the LED, from the power supplied in the switch am i able to route the power from the illumination of the A/C Control Panel.....as i have shown in the picture:
posted_image

these are 12V LED Bulbs by the way, so they have resistors etc inside.
by running the extra wires indicated by the green lines in the picture above, would it work?
and by wiring in such a way, would I possibly run into any problems down the track?, such as blown fuses, burnt leds, etc?

thanks for your help :)

Replies:

Posted By: Teken
Date Posted: August 18, 2004 at 9:10 PM

The LED's require a resistor to be placed (*before*) in series with the circuit in question.

That is why you are burning up the LED's. The resistor to be placed in series is dictated by the LED you are using. Read the maker(s) current / voltage specifications to determine the value.

Regards

EVIL Teken . . .

Posted By: terrynham
Date Posted: August 18, 2004 at 11:24 PM

but these are LED Bulbs.....so they already have resistors inside them....
because with the other LED Bulbs i put in else where, they work perfectly fine without burning.....only the demister switch is burning LEDs.....

like in the picture i drew. The two LEDs i put in the A/C Control Panel they both work fine, without burning.....
so if i run another wire in parallel, indicated by the 'green lines' in the picture. Would that work?

thanks.

Posted By: terrynham
Date Posted: August 21, 2004 at 6:02 AM

sorry for double posting posted_image

, but i really need to find out if my above idea will work?

technically the Demister switch shouldnt be burning LEDs, because in the A/C Switch the LED i put in there works fine......and they are the same thing pretty much.....
so if i wire the extra LED in with the A/C Control Panel Lights (as illistrated above)......and then shove the LED into the Demister Switch (which i can do posted_image

)
would that work? or will i overload something or burn something else? (i know extremely little about electrics, but i am interested to learn posted_image

)

thanks again.

Posted By: Teken
Date Posted: August 24, 2004 at 11:09 AM

Sorry I did not reply earlier, for some reason I am not recieving all my notification to threads I am subscribed to.

Moving on . . . I think one of the main things you are misunderstanding is that you are appying a LED that requires a higher rated resistor then there is in place now.

I would change the value, from what ever it is, and add another 100 ohms to it. That is the only reason that a LED would burn out, other then having the LED wired backward, or the working voltage is too great.

Try that first.

Regards

EVIL Teken . . .