Anyone had the same problem? I noticed it yesterday while brushing snow off the car. Light has a dim glow which seemed to pulsating in regular intervals.

Could it have something to do with the leds I´ve used to replace regular bulbs?

Or is just that the car is in carage that has temperature of around 35F when its around 5F outside, so maybe some condensating in electrics? Everything else seems to be okay, even driver door which door ajar switch is acting up now and then. BTW does someone know, what is the color of wires going to door switch?

Thanks guys..

 

repkim, I am venturing to guess that you are seeing an issue that we have with our cars. Installing LEDs in certain places on the car results in the LEDs glowing very faintly because the way that the circuit is set up in the car, the bulbs actually get a very slight current sent through them. With incandescent bulbs, this current is so small (less than 0.001 amps), that the bulb will not glow. But, due to the design of LEDs, they can actually take that little bit of power and make some amount of light from it. This all stems from the fact that the bulbs are powered via an electronic switch vice your standard switch.

 

Thanks Thermo, i was kinda expecting that you could have some clue about this..

I think I didn´t describe problem right in the previous post. 3rd brake light is the original Raytheon led module. I´ve changed rear lamp brake lights (5W/21W) and side markers (T10). Could this really effect the 3rd module? Is the idea that leds pass more power through them and that goes to 3rd brake lamp? I myself suspect problems with grounding.

Well, easiest way to find out is to put regular bulbs back in the housing and try again. If that is the problem then it´s best to replace bulbs with canbus leds. That should take a way the problem.

Thanks

 

Repkim, LEDs are a strange monster. They do not operate like a traditional bulb. If you try to measure the resistance of a standard incandescent bulb, you will get a fixed resistance (ie, the resistance of the metal wire inside the bulb). So now, as you apply electricity to it, it will flow the amount of current that is related to the voltage applied divided by the resistance measured (Ohm's Law). Nothing special is needed to be done for a basic bulb circuit.

Now, when you get into LEDs, you can think of them working the exact opposite way. An LED varies its resistance in an attempt to maintain a constant voltage across the LED. In a lot of cases, the LED attempts to maintain roughly 3.6 VDC across it (some are 1.8, all depends on how the LED is manufactured as to what this voltage will be). It doesn't care what current that requires (Ohms law still applies, so, now voltage is relative to resistance times current). If you have an electronic switch (like that used in the computers of the car), they truely only provide a high resistance to a circuit making it so that a very limited amount of power makes it to the component, making it appear that it is not working. In the case of the LEDs, they are fighting this system and attempting to get their designed voltage across them. So, they are changing their resistance to get the voltage and in some cases, the current can be enough for it to emit visible light. On the flip side, if you do not limit the current going to an LED, it will attempt to flow tons of it. I liken this to you trying to put a dump truck load of dirt into your car. It may fit, but your car is not going to like it due to too much weight. In the case of an LED, if it flows too much current, it will literally blow up (yes, like pop goes the weasel and the pieces do hurt). That is where an engineer or someone familiar with electronics has to pick an appropriately sized resistor to match the LED to the power source to prevent the LED from getting too much power and destroying itself but also giving it enough to allow it to make its full amount of light.

In your case, how the LEDs are wired up (numerous ways to limit the current to LEDs), one may be using a simple resistor in series while the other is using a complicated circuit. What this can do is backfeed power from one line to another. For example, I bet if you remove all of your combination light (brake/running) bulbs, you will find that your 3rd brake light issue will go away. This is because of the circuitry inside of the LED bulbs allowing a small amount of power from the running lights to feed back into the brake light circuit.

Gotta love electronics. They can do some strange things and figuring out why they are doing it can be frustrating.

 

Thanks Thermo, one gotta believe the smarter ones than themselves..

BTW typo with the module. Visteon not Raytheon..