Seeing PWM Data

[wpoll]

Originally Posted by oldskewel

You're talking about one of the mysteries of my 2001 3.0i that has puzzled me ever since I came across it. All my lighting is stock. No LEDs retrofitted.

Why does BMW specify dual filament bulbs (specifically for the front turn signal / parking lights) and then only send two wires to the bulb? I've asked that a few times on here, never with a real response. Any thoughts?

I did not check to confirm whether both filaments light up when installed and lit. Confused, but can live with that.

Question. As there are two possible OEM lighting options with a 2001, Xenon and non-xenon, does one or both have a small 5w "pilot" lamp in the low-beam or high-beam reflector? If so, this is possibly the "parking lamp" mentioned in the wiring diagrams - module E15.

https://www.newtis.info/tisv2/a/en/e...t-left/ochLgrP

This would explain the extra lamp that made no sense to me - as the LCI cars use the halos in this role.

This means that the signal/side lights are module H7.

https://www.newtis.info/tisv2/a/en/e...e-left/bNBYXcs

No idea why they have dual filaments but now that you mention it, I recall that coming up before...

[andrewwynn]

My take on the dual filament one used is for part number simplicity. Also in a way a built in spare.

If the brake light goes out you can switch with a run light which has an unused brake filament. I found it very odd myself and the answer I came to is purely speculation.

I was very surprised to find out the front corner lights don't use the low filament of the dual filament bulb for either run/park/corner or for the dim parking mode. I tried some led in the front and had to go back to Incan.

I left the back turn signal LED though and they are stunning bright. Make no mistake when I've got a signal on from the back.

[andrewwynn]

Neither of our cars have DRL which I would think woukd be that 5w mystery bulb. It could be there just disabled or LCM could use high beam filament for DRL. Why not using both filaments for run/flash in corners is a real mystery

[wpoll]

Originally Posted by andrewwynn

Neither of our cars have DRL which I would think woukd be that 5w mystery bulb. It could be there just disabled or LCM could use high beam filament for DRL. Why not using both filaments for run/flash in corners is a real mystery

The 5w lamp wouldn't be a DRL - not bright enough (like the halos).

What lighting do you get on the first (clockwise) click on the manual headlight switch? The "park" position.

I get halos up front and four red tails (top and bottom, both sides) at the rear.

[upallnight]

The 5w bulb are known as "city light" normally found on European cars and not USA cars. Just like rear fog lights are not normally found on USA cars, but are a requirements on European cars.

[wpoll]

Originally Posted by upallnight

The 5w bulb are known as "city light" normally found on European cars and not USA cars. Just like rear fog lights are not normally found on USA cars, but are a requirements on European cars.

Of course, the 5w lights were replaced by the halos (AEs) in all markets.

Be nice if everyone could agree on things like this. Ain't ever gonna happen though, is it?

[jsoto]

Gosh. Lots to reads. I don't really know what the lumens specs on the rings are but they are really really bright. Hopefully I can get the intended goal to work *switchback amber portion of the ring* in true wired fashion with no wonkiness. The amber is even rated 2X brighter than the daytime white of the rings. I'm really impressed so far about the rings.

Interesting read so far AW on your experience with LED turns in the front. I might have crossed that bridge if I had have the correct bulbs.

Anyhow, I think we have a new plan of attack. Will update if does the trick. in rough reading, I think it may

[Zulu95]

I remember back when I first gt the x/scope I put it on the parking/side/turn signal. There was a spiky 20k wave form of around 4v peak for the parking et al and full power for turn signal flashing off and on as they do. Now the LKM died in this vehicle a few months later so anything I saw I treated as slightly suspect as the failure may have "colored" the waveforms displayed.

[wpoll]

Originally Posted by Zulu95

I remember back when I first gt the x/scope I put it on the parking/side/turn signal. There was a spiky 20k wave form of around 4v peak for the parking et al and full power for turn signal flashing off and on as they do. Now the LKM died in this vehicle a few months later so anything I saw I treated as slightly suspect as the failure may have "colored" the waveforms displayed.

I would expect the PWM signal to be a square wave with a peak value of around 12v. Not sure of the frequency but I'm sure I've heard my (bad) tail light connections "sing" so the frequency is likely within the audible spectrum (20Hz - 20kHz), most likely around a few kHz.

I REALLY need to go and find my Fluke 'scope Meter.... it's on loan to someone and I cannot locate it...

[jsoto]

I do think the root cause was right in front on me but I did not see it as I was not thinking straight. With lows on, the parking lights are enabled, and that was the trickle down effect from there.