DRL with my JWS 8910 lamps

Hi

Can my JWS 8910 lamps use the GM DRL feature in my 97 Tahoe?

I suppose the question perhaps should be clarified by asking directly if the lamps could be damaged by using the low voltage stock DRL module/circuit? I currently have the DRL module disconnected.

I know that the lamps have a "built in" led for DRL use but I would need to wire a suitable power source for this. Would be much easier just to use the GM circuit if possible.

As always, I appreciate the knowledge represented here.

The lamps will be fine, but they'll be running at full output levels in DRL mode, which is not legal unless the vehicle has an ambient light sensor to turn on the rest of the lights that are required with headlamps when it gets specifically dark enough outside (that's the front position/parking lights, rear position/tail lights, side marker lights, license plate and dashboard lights). Unlike filament lamps, the LED headlamps do not operate at reduced intensity when fed a reduced voltage signal; the driver circuitry built into the headlamps keeps them running at full output across the full allowable range of input voltage.

I'm looking at the JW Speaker 8900/8910 data page and it deosn't say anything about a DRL function. It does say they have a front position (parking) lamp, which is not legally or safely usable as a DRL (not even close).

A good way to have DRLs without causing or risking new problems would be to leave the stock DRL disabled, moving the DRL function to the front turn signals as described here.

On a couple of my older pickup trucks in Canada, the factory DRLs drive the incan headlamps at 6v.

I wanted to try this with the JWS 8900s & then the 8910s, but I was told that since they require a minimum of 10v, the high beam drivers would get damaged.

I ended up wiring in Dan Stern's DRL-1 module a few years back and interrupting the factory DRL module's speed sensor wire so I'd still get the high beam indicator on the cluster.

Never quite been sure about what to do with the front position markers...wire them in with the park lights?

"Front position markers" is sort of a mashup of functions that actually exist: front position lights and side marker lights. I am assuming you mean the front position lights built into the JW Speaker headlamps. "Front position light" is the formal name for what Americans call "parking lights", so yes, that's how they should be hooked up. Either along with or instead of your vehicle's original parking lights (often a low-intensity filament in the turn signal). If your vehicle has wraparound parking lights that also provide the front side marker light function, it will need to be "along with" and not "instead of".

And yes, you got good advice/made a good decision not to try running the LED headlamps on reduced voltage as DRLs. The only three results that can happen are illegal/unsafe DRL operation, or damage to the expensive LED lamps, or no DRL function at all (or I guess there's a fourth: some combination of the other three).

Yes, the front position lamps built into the JWS; I tend to call the factory lamps "park lamps", old habits die hard for us dinosaurs.

The fourth "combination" option doesn't sound good

On a side note, Dan Stern sent me a prototype module last year, which replaces & enhances the original DRL-1.

Heavier duty, higher spec parts inside with full potting etc.

Not only does it add DRL functionality like the DRL-1, but a single module can also add flashing side marker functionality if desired; more cost effective & a cleaner install than 2x DRL-1s.

DRL+ as a moniker was what was arrived at last year....

My observations - works flawlessly. The module shape/design makes it easy to secure to an isolator and screw down, if desired.

A short vid Dan requested last year, while I visited the city -

1/ turn signals
2/ DRL + turn signals
3/ Park lamps (I guess I had the JWS 8910 fp lamps wired in to the park circuit last year).
4/ Park lamps + turn signals.

I've been hearing about the new module-in-the-works from time to time from Stern, but this is the first I've seen it in the wild. Looks like it does everything it's supposed to, and yeah, I like the idea of a single multifunction module rather than having to put one module for DRLs and another to add turn signal repeater flashing to the side marker lights (and yeah, I really like the idea of heavy-duty/potted/etc).

Speaking of "in the wild": that has got to be the winningest paint job I've ever seen on one of those trucks.

That Stern, always thinking, always improving products. Not a single hitch in a year of daily driving.

Ah, I did a frame off/body/interior/powertrain refresh/drivetrain etc. a few years back on this old truck, and decided to use my left over SubLime from a previously done GTX, as I was too cheap to buy new paint.

Is that lag in the module or just a *huge* difference in the filament rise times?

Thats because the fronts are incandescent bulbs, and the sides are LEDs.

That's my careful engineering to halfway simulate the front-sides alternate factory flash mode.

Alaric Darconville said:

Is that lag in the module or just a *huge* difference in the filament rise times?

Click to expand...

Ofelas said:

On a side note, Dan Stern sent me a prototype module last year, which replaces & enhances the original DRL-1.

Click to expand...

I'll need one for my LS430. It has high beam DRLs now, and I'm loath to put in HIR1s until I move, or possibly outright disable, the DRL function. I'm too cheap to buy two of the original ones to add the markerflash functionality, too, so a DRL-2 (ha, better name since one can replace two and it's more than twice as good!) would be just the thing.

Any word on the "new" version (or even the old one, as I haven't heard back from Daniel Stern at his torque.net address)?

I've got a car with DRLs on the H7s apparently using PWM at 80 Hz, so it is a mess to wire up driving lights without at least two relays and kick-back snubbers[1]. I'd rather get the DRLs off the H7s to potentially preserve their life (field programmable) and only use a single relay for the driving lights.


[1] The DRLs come on in the "parking light" position, so that's out. The high-beam indicator is driven off CAN, from what I can tell, and I'd rather not tear apart the secondary instrument cluster.

As far as I know, at least the "old" version is still readily available from Stern. Don't know what the status is on the "new" version. Last I talked to him about 10 days ago he was sick/stuck in bed; maybe that's why he's not answering mail.

If someone has one of these installed, would you be able to report if the front indicators under DRL operation are out of phase (fronts blink off as rest blink on) or not?

I'm considering building and potting my own and, unless I'm missing something, the logic is more straightforward and stateless if out of phase.

turn_power = (park_sense and turn_sense) or (!park_sense and !turn_sense)

Which likely can be implemented with two transistors and a P-channel, enhancement-mode MOSFET per side (plus a couple resistors and zener diodes for spike protection).

They are in phase -- as required by law. The side marker lights can flash in counterphase with the front/rear signals, but other than that all turn signals (front, rear, side repeaters) must flash together in phase.

Beyond that, I think you are going to find the logic for correct, problem-free operation isn't quite as simple as you presently have in mind.

Ya know Virgil, the alternate flash is the only thing I miss after putting Philips amber LEDs in the side markers.

So much so that I'm considering reinstalling 168 incans, removing the isolated ground, & splicing that wire back to the front marker flash circuit like OEM.

jeffsf - while DIY is a wonderful thing, why not just pick up a DRL or DRL+ module from Stern, seeing as he has contributed so much to our lighting needs?

Thanks to you both. I already purchase from Daniel Stern when I can. A potted, tested unit would be my first choice. Regrettably, I've heard he's been under the weather recently and I haven't heard back from him in a while.

Were it a handful of robust components that I could pot, adding to my component order for the driving-light harness and some other projects would have been an option.

I agree that if the fronts need to be kept in phase with the rest, the logic is non-trivial. One would need to detect the turn signal becoming "activated" then pick it up on the falling edge of the sense line, later sensing "deactivated" and restore the DRL illumination. Getting a microcontroller or discrete logic to "100% reliably" run off car supply is far beyond a handful of components.

Ofelas said:

Ya know Virgil, the alternate flash is the only thing I miss after putting Philips amber LEDs in the side markers.

Click to expand...

Why? There's no advantage to it.

So much so that I'm considering reinstalling 168 incans, removing the isolated ground, & splicing that wire back to the front marker flash circuit like OEM.

Click to expand...

You could have both with a couple of NC relays, but again...why?

As for Stern, I heard back from him this morning on an email I'd sent multiple weeks ago, so I guess he's still alive

Ah, nothing else except the aesthetics of an alternate flash, I suppose.

I'll stop looking at shop windows while I'm making a turn with both front & side markers flashing

Good to hear that Stern's surfaced; I'll holler at him & see where he's at on more DRL+ modules, couple local fellers want me to wire them in come Spring.

-Virgil- said:

As for Stern, I heard back from him this morning on an email I'd sent multiple weeks ago, so I guess he's still alive

Click to expand...

He didn't kick the bucket, he just turned a little pale.

Ofelas said:

Ah, nothing else except the aesthetics of an alternate flash, I suppose.

Click to expand...

Alternate flash when the parking lamps are on is expected from a particular wiring method, but if you're going to use LEDs and electronic modules you might as well have synchronous flash both with parking lamps off *and* on.