Rennlist - Porsche Discussion Forums - Interior LED Changeover (uhm...Looooong)

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Paul, thanks for sharing your experience with this.

Hope you're settling on a solution that works for you.

Quote:

Originally Posted by SQLGuy (Post 9480599)

1. I also used the WLED-x5 lamps for the backlights. In order to allow these to fit through the stock holes, I had to grind down the side LEDs a bit with a drum sander on a Dremel. No harm from the sanding, though... if anything, it provides a bit of an improvement in lateral dispersion. I also found that I had to push the leads all the way to the outside, at the bottoms of the lamps, in order to get them to make contact with the contacts in the holders.

I didn't need to do that, but in my write-up, I did mention that those WLED-WHP5 bulbs (using the original brown twist-lock sockets) are best inserted after the bulb PC board is reattached to the white plastic piece and you still need to jiggle them a little to get them inserted.

Of course, the bulbs you got might have been ever so slightly different. It seems that the manufacturing tolerances on these bulbs aren't real tight. :)

Quote:

Originally Posted by SQLGuy (Post 9480599)

2. I bought green and red lamps for the LCD display. In the end, though, I decided to stick with the stock incandescents, as the LEDs (the cheaper/dimmer B8.4D's) while being a good brightness, still made for too much of a spotlit (i.e. uneven) backlighting of the LCD panels.

I recommended the B8.4D-AHP (amber for the four uppers) and B8.4D-RHP (red for the four lowers). Note the "HP" (high power) suffix; these are both brighter and have a more even, wider field. Believe me, I did a lot of experimenting with different products before coming up with my recommendations. :)

The B8.4D-xHP versions look like this (this happens to be a blue one; you'll want amber and red for the LCD "information display" backlighting):

https://lh4.googleusercontent.com/-R...1-05-0167a.JPG

I've already posted these photos in other threads, but a fully populated instrument cluster bulb PC board using the LED bulbs I recommend looks like this:

(Click any of these photos to see them in their full high-res glory)

https://lh5.googleusercontent.com/-m...11-05-0380.JPG

https://lh4.googleusercontent.com/-G...11-05-0383.JPG

And you'll see that it's rather nice, even lighting; the info display backlighting isn't perfectly even, but it's pretty darn good.

The photos don't quite do it justice, either. It's hard getting good photos of the cluster in the dark, and I've noticed that LEDs show some weird color shifting and brightness differences in photos that you cannot (or can barely) see in person.

https://lh4.googleusercontent.com/-i...1-05-0472a.JPG

https://lh5.googleusercontent.com/-q...1-05-0520a.JPG

https://lh5.googleusercontent.com/-a...1-05-0462a.JPG

https://lh3.googleusercontent.com/-e...1-05-0457a.JPG

Looks like you're using the WLED-x5HP's in that shot. The regular WLED-x5's use lensed LEDs rather than surface mount ones.

I had thought about amber, but when I shined a light through the LCD (power off) it transmitted more green, so I that's why I went with green. From your shots, I think the amber probably is a better call, though.

Thanks for sharing.

Paul

Keith:

Thanks very much for this excellent article. I've been looking for this type of info for a long time.

Barney

I am nearing the end of my dash LED conversion, and all that is left to do is the switches. I was looking for the blue/black wires on each of the switches, but I noticed that on the 4 way flasher switch there are two blue/black wires. Can I solder the resistor to either of those wires? I just want to make sure before I dive in head first. Thanks!

Quote:

Originally Posted by Simon928 (Post 10200057)

I'll try to remember to update the document to include that detail when I get home this evening.

I'll just quote (and bold the most relevant parts) an exchange from another thread that answers the question:

Quote:

Originally Posted by Ed Scherer (Post 10175535)

Quote:

Originally Posted by Tony (Post 10175507)

hi Ed...can you clarify the purpose of the resistors on the pod switches.

is it to establish a preset level of brightness when the lights are turned. from that level the dimmer would take them dimmer but never any brighter.....i think that is the reason.

with my lights off, the only switch lit is for the headlights....as it should be. I dont have any other "residual" voltage that would cause any other pod light to light up or faintly glow.

my hazard unit (87s4) has two black/blue wires...do i place a resistor on both.

thnx

The resistors preserve the functionality of the back-lighting being at two intensity levels based on the state of the switch (or function related to the switch). This is separate from the overall dimming achieved by the dimmer rheostat. Without the resistors, with the dimmer rheostat set to full intensity, you wouldn't be able to distinguish between the on/off states. These resistors are actually just adding resistance to already-present resistors in the switches that are—after replacing the incandescent bulbs with LEDs—of too small resistance to have any significant effect on the lower-current-drawing LEDs. If you look at the WSM schematics, you'll see those already-present-in-the-switches resistors in the internals of the switch (they're just shown as rectangles with unspecified resistance, always wired to terminal 58 that the BK/BL wires connect to).

In the case of any switches with two BK/BL wires, the resistor goes between the switch contact and the two wires (the two existing wires are just daisy chaining to elsewhere and you want to preserve that connection without any resistance).

Thanks for the reply, and thanks even more for the excellent guide! I wouldn't have even attempted the conversion without it.

In the case of my two black/blue wires, they are both joined inside the switch. Short of trying to pull out the wires and re-connect them, could I just put a resistor on each wire?

Quote:

Originally Posted by Simon928 (Post 10200179)

Thanks for the reply, and thanks even more for the excellent guide! I wouldn't have even attempted the conversion without it.

You're welcome!

Quote:

Originally Posted by Simon928 (Post 10200179)

In the case of my two black/blue wires, they are both joined inside the switch. Short of trying to pull out the wires and re-connect them, could I just put a resistor on each wire?

No... the two BK/BL wires must remain connected with no (added) resistance between them. IIRC, I cut them far enough away from the switch that it left enough to work with and then just put the resistor between each pair. Just think of it as the same wire that happens to be split into two pieces. :) After you strip enough to solder to (and remembering to put the heat shrink tubing on before soldering!), just twist each pair of two wires back together again along with the end of the resistor, e.g.

Code:

             /----BK/BL wire 1----\                /----BK/BL wire 1----

term. 58 ----|                    |----resistor----|

             \----BK/BL wire 2----/                \----BK/BL wire 2----

Cool, that makes sense. Now I'm gonna get out my soldering gun. I'm pretty useless when it comes to electrical stuff, so this has been a huge help. Thanks again!

Question: what bulbs does one use to replace down next to the AT shifter in earlier cars? They're different from others used throughout the car, and emit a horribly dated orange glow and I want to change them to LED.

Quote:

Originally Posted by brealytrent (Post 10230819)

Get the 5sp shift boot and get rid of that bit of redundancy. You have indicators in the inst. cluster for what gear your in.:thumbup:

Quote:

Originally Posted by Tony (Post 10231861)

Get the 5sp shift boot and get rid of that bit of redundancy. You have indicators in the inst. cluster for what gear your in.:thumbup:

Umm, actually I don't. haha, is my '84 supposed to have the indicators in the dash as well?

Its a bit OT in the fact its an exterior LED but what is the bulb type for replacing the reverse lights...

I know i have seen it on here some where but the search eludes me this time.

Quote:

Originally Posted by Tony (Post 10249557)

Its a bit OT in the fact its an exterior LED but what is the bulb type for replacing the reverse lights...

I know i have seen it on here some where but the search eludes me this time.

See My recommendations for exterior LED bulbs on '90 S4 (should mostly apply to '87+). I'm pretty sure that the SuperBrightLEDs 1156 LED Bulb - Single Intensity 45 SMD LED Tower that I recommend there are also the ones that I show in a post that shows a "promising LED" compared to the original incandescent bulb. FWIW, I'm still not satisfied with these; I hope to eventually find something brighter.

Still wondering if there's a replacement for the ones that light the transmission gear #s on the center console of earlier auto cars?