[keystone183]

Ok, so i know this has been discussed quite a bit lately, but i feel like there haven't been any hard and fast answers. I installed the map lights and dome lights in my '11 and had problems with them working correctly when the key was in the off position. As per some other members, installed a 150ohm 1 watt resistor and this fixed the problem. However, there is still some feedback in the speakers when i switch on the leds.

I am not an electronics or electrical genius by any stretch of the imagination, and don't have a good grasp on the concepts here. My questions are:

1. Why is this necessary.
2. What if any adverse affects might there be on the system?
3. Is this the correct way to wire in the resistor?
4. Is this really the best resistor to use?

Appreciate the help in solving the problem, just want to understand why this is working. Thanks.

 

[dodgert]

Buy from superbrightleds.com and u will have 0 problems all leds are plug and play and you need no resistors as they are in the lights i have them in all my interior and exterior lights and have 0 problems.

 

[keystone183]

That seems to be the common thought, but I'm here to tell you that just isn't the case. I've got three different bulbs over two orders and same problem in two separate locations.

Have you tried yours with the key in the off position?

 

[dodgert]

Yep key off key on have yet to exp any problems where did you order them from

 

[keystone183]

superbrightleds.com. Three different bulbs (different styles). Two different orders. Again, they worked fine with the key turned to acc or on, but not with key in off. put resistor in, work fine. Which brings up my questions.

 

[keystone183]

Ok, so i know this has been discussed quite a bit lately, but i feel like there haven't been any hard and fast answers. I installed the map lights and dome lights in my '11 and had problems with them working correctly when the key was in the off position. As per some other members, installed a 150ohm 1 watt resistor and this fixed the problem. However, there is still some feedback in the speakers when i switch on the leds.

I am not an electronics or electrical genius by any stretch of the imagination, and don't have a good grasp on the concepts here. My questions are:

1. Why is this necessary.
2. What if any adverse affects might there be on the system?
3. Is this the correct way to wire in the resistor?
4. Is this really the best resistor to use?

Appreciate the help in solving the problem, just want to understand why this is working. Thanks.

OK, at the risk of sounding like an arrogant bas**** and answering my own questions, here goes. I talked to a friend of mine tonight who is an engineer (not electrical, but he payed attention in college) and this is what we were able to come up with. PLEASE, feel free to chime in here.

1. Apparently, the computer must be reading the circuit as broken when replaced with led's. When the key is turned on, there MUST be some other source on the circuit (radio, dash, SOMETHING) that is pulling enough power to fool the computer into not seeing the maps/dome as being off. Putting in the resistor tricks the computer when the key is off. (I have NO idea why the computer is monitoring the map light circuit???)

2. Should be none. The resistor is creating heat??, but hopefully not enough to be an issue. I have taped over most of the exposed leads, and the circuit board of the leds to keep from having any shorts. Had the doors open (domes on) for a substantial period today vacuuming/cleaning the interior. The resistor-ed map was substantially hotter than the non, but not dangerously (i hope). Nothing caught fire anyhow....

3.Yes. Wiring it parallel doesn't reduce the voltage feeding the the leds. This means the brightness shouldn't be reduced, but the overall impedance of the circuit is increased, so the computer is still fooled.

4. Don't know. I have a voltmeter, and have a basic understanding of how to use it, but need to actually do it, and then give the results to someone who know how to read them. More on this in the future.

This was an extremely long winded post, and if you made it to the end hopefully i'm not completely off here. I would LOVE any input on any of this. Thanks.

 

[johnnyG]

You need to 2 know the specs of both bulbs before you can figure ut what resistor to use. You need to know the current draw of the halgen bulb and compare it to the current draw of the LED.
My guess is the current draw for the LED is practically nothing and is causing the on/off of the lights. I would try between a 60-100ohm 1/4watt resistor across the contacts. Meaning stretched across from one side of the bulb terminal to the next, just as the light bulb does. This will draw a little more current and should keep the lights on steadily.
60ohm will add 200milliamps= .2A ans 100 will give only 120milliamps = .12A
Running the resistor from one side and grounding it out will do absolutely nothing. Current will flow through the easiest route which won't be through the resistor that's just grounded out, there needs to be sucking power from the otherside such as the bulb. You could cut the lead wires and wire in the resistor in series as well which is te best route here, but there is cut/splice involved. <<<---You may have to cut/splice if the accross bulb trick don't work because you are essentially changing the current at that point and you may actually reduce it due to running parallel with the bulb?? Resistors ran in parallel reduce everything but voltage."

that was sent to me by Ryan Hall at superbrightleds.com. he said he has this problem with a lot of dodge trucks and has had to deal with sending this message out many times. it actually came from another forum. so what i did was use a 1W 100 ohm resistor and have not had a single problem since. it has been on for a few months now.

 

[dodgert]

Guess i got real lucky as i have all leds in all my interior and ext lights and no problems had to get res for the tail and turn sig but they were real easy to install.

 

[johnnyG]

yeah you did. i am sure others got lucky as well. then again i did all the interior with hvac controls headlight knob and instrument gauge cluster and overhead evic. so the total loss of resistance might have something to do with it. then again every truck is different and the same.