DRL-1: to synchronize or not to synchronize

Hi gents,

I recently installed the DRL-1 module on the Alero. Great product, easy to install, works exactly as intended.

The documentation says that having the opposite turn side bulb turn off or stay on while signalling is a matter of personal preference and that both are valid.

Stays on: You still have your DRL on the non signalling side, but it could cause confusion

Turns off: no confusion but now the non signalling side has no DRL.

I am pretty sure OEM's using turn signals for DRL's have it both ways, which doesnt help decide.

Its probably not too important in the grand scheme of things, just wondering what y'all think.

Cheers
Dave

Factory turn signal DRL systems all keep the other-side lamp lit steadily (as a DRL) while the signaling side is flashing. I think that's the best way to have it, because otherwise if you're sitting in the middle of a street waiting to turn left across traffic you have no DRLs at all, just one flashing turn signal. In fact, there are some (non-turn signal) DRL systems that turn off or dim the DRL on the turn signal side while the signal is flashing, but I can't think of any DRL systems (of any type) that turn off the DRL on that side while the turn signal is flashing on this side.

Thanks for the info. Why do they offer the option to choose if the OEM's seem to have settled on a standard way, IE leaving the "other" side illuminated?

I don't know. Probably customer demand -- notice how they also sell stuff they shouldn't be selling (CHMSL flashers, turn signal sequencers).

Ah, I had never looked at their website, as I got my DRL1 unit through Mr. Stern with my whole headlight package.

Its sad to see that a company that sells such a good product is also selling those other items. Bet they sell 10 flashers for every DRL1.

-Virgil- said:

Factory turn signal DRL systems all keep the other-side lamp lit steadily (as a DRL) while the signaling side is flashing. I think that's the best way to have it, because otherwise if you're sitting in the middle of a street waiting to turn left across traffic you have no DRLs at all, just one flashing turn signal. In fact, there are some (non-turn signal) DRL systems that turn off or dim the DRL on the turn signal side while the signal is flashing, but I can't think of any DRL systems (of any type) that turn off the DRL on that side while the turn signal is flashing on this side.

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Say a Tesla Model S, and the signal side turns off the LED drl, and the opposite side decreases in intensity from DRL output, to parking level output.
Nice, very polite.

Actually, on the Tesla Model S, the signal side dims the same-side LED DRL to parking lamp intensity. The other-side LED DRL remains at full DRL intensity. That's exactly the right way to do it with LED DRLs in proximity to the turn signals.

Maybe that was they way they used to do it. But I saw it three days ago.
And Tesla is big into incremental over-the-air software updates.

And I saw it half an hour ago, which is more recent than 3 days. I'm pretty sure you did not see what you thought you saw, or perhaps you saw a car with a fault. For one thing, what you describe is not a legal arrangement. A DRL may (or must, depending on photometrics) extinguish or dim while its same-side turn signal is operating, but there is no legal provision for the opposite-side DRL to extinguish or dim. See posts 2 and 4 in this thread.

Also, the local Tesla dealer is a block from my office, and I'm on a corner with a traffic light; not only do I see a lot of Teslas with DRLs and their turn signals operating when I'm just looking out my window, but I've also spent enough time at the dealership scrutinizing the lighting on the cars that they know me well enough over there to bring me a coffee and come chat with me.

-Virgil- said:

....... I've also spent enough time at the dealership scrutinizing the lighting on the cars that they know me well enough over there to bring me a coffee and come chat with me......

Click to expand...

I don't know if I have enough self control to resist asking for a lively demo in Extreme mode. Errrr...but only to see how well the headlights function under severe acceleration. Yeah, that's it....yup, purely a scientific endeavor.

Am I tempted? Yes. Do I know better than to push my luck? Also yes!

Worth mentioning: the Tesla Model S is (yet) another datum against the common internet-fanboy meme that European-spec car lights are "just better". The US cars get a 35w HID projector headlamp with 3200 source lumens. The Europe-spec cars get a 25w HID projector headlamp with 2000 source lumens (so that no headlamp washer or self-leveling is required). Optical efficiency in the two headlamps is effectively identical, so that's about 38% less light in the beam on the European models.