New LED bulb with resistor

[slowmover]

I'd ask the retailer. They have a good reputation. The DODGE I own has a rep for being picky about electrical loads the CAN BUS system cannot read well. But it may be different than the Euro models cited in ad copy. Etc.

[brucepick]

I went to the link for the LED 1157 bulbs in the first post here. The seller - and I consider SuperBrightLEDs.com one of the leading sources in that field - says:

"The load resistor built into CAN bus bulbs are not intended to fix turn signal related issues, such as hyperflashing."

Sorry to say, I think that tells us right there - this bulb does not solve that problem. But take heart, LED replacement of the turn signals could be worthwhile. Read on.

The bulbs are designed to work with the European CAN system, whatever that system may require of the bulbs. I did some quick googling and didn't yet find an explanation of what that is.

We owned 1980's and early '90's Volvos for many years, that had a bulb failure detection circuit. I'm sure it was not the modern CAN system, however it was so sensitive that it would indicate a bulb failure if you had two bulbs of different ages (which I've seen can cause maybe a 10% resistance change) or even from different batches. It looked for differences in the current flowing in the left vs right side circuits.

Anyway - - -
I understand a bit about the blinker's need for resistance in the bulb. Here's my take, especially with regard to our interest I reducing power demands.

An LED version of the 1157 bulb - or for similar dual filament bulbs made to serve as brake and running lights - needs a resistor added to the blinker circuit, so the LED bulb will appear as a regular one to the flasher relay. You wire the resistor in parallel with the bulb, so the resistance of the combination is reduced. And it's power consumption (watts) is now essentially equal to a standard bulb. If it were not nearly identical to a standard bulb, the flasher would be too fast or too slow.

Get their approx $25 bulb. Thats what i got for my brake lights (but they were the other base connector type, you need 1157 for fronts). You will only be wiring the resistor for the turn signal. Not for the running light circuit.

So the running light will give you all the power savings you should get by using an LED bulb. In my view that's what counts, because they stay on when you drive with headlights. The flashing part will consume power like a regular bulb but its not such a big problem. It's only on for a short time, and even then is off half of that time.

That's why I'd consider doing the swap if cost and time availability aren't an issue.

Somewhere (on the SuperBrightLEDs site?) I saw a writeup of what resistor to use. You would need one for left side and one for right. It mght benefit from a soldered connection because the whole reason for the resistor is to control (reduce) resistance. You don't want corrosion in a crimp connector or some such issue to mess it up later.

[brucepick]

Originally Posted by 3dplane

... The factory headlamp was designed to throw light in the correct directions and angles with minimal light spilling based on the EXACT location of the light source in the fixture, which is the filament in the bulb that it was designed with.

If we change this location within the fixture,(different bulb or incorrectly installed bulb)the mirrors behind the bulb will throw the light in all kinds of directions except where it needs to go...

3dplane is exactly right on this. The headlight has a carefully designed reflector that's based on the glowing filament being in exactly the right spot. Unfortunately an HID glow spot has a different shape and size from the halogen's so the systems focus is not the same. They might get some of the glowing field in the pinpoint where the halogen had it, but the rest of he HID's glowing field is in some other place where it's not supposed to be.

The low beam concentrates light on the nearby road surface and spares oncoming drivers from glare. The high beam is close to a pencil beam so it is effective at a distance, with relatively little spreading. Both need aiming but in practicality, if you aim the low beam right the high will be ok (assuming one bulb is doing both jobs like in our Civics).

[Cobb]

Some cars measure the resistance of the bulb and gives you a reading of its lifespan. This way you see if your bulb is new, worn or needs replacing before it burns out. A friend of mines with an AMG Benz has this. He also have push buttons to raise and lower the car.