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I installed the LEDs and made some measurements last weekend. The LEDs are a huge improvement over the old bulbs but they make the dirt on the inside of the gauges' lenses obvious so I'll have to take them apart and clean them!
The rheostat puts out 0 V when turned fully counter-clockwise. Turning it clockwise, a click can be heard and the voltage jumps to 9.3 V. At fully clockwise, the voltage is 12 V. This is with the engine off so it'll be higher when the car is running. The LEDs come on at approx 7.5 V so they're already pretty bright when the dimmer switches on at 9.3 V. There is some dimming through the range of the rheostat but not much. Still, it's good enough for my needs so I'll leave it alone. If one wanted to increase the dimming range, a PWM circuit would work but I would personally use a power op-amp that scales the output of the dimmer to suit the LEDs.

Thanks for posting you results. I think that confirms that the dimmer in the light switch is not consistent, and depending on the condition it dims different. As an example, the LED's in all my 3 cars (71, 82, and 87) don't turn off complete as yours.

Thanks again
Engelbert

I'm afraid I wasn't very clear - the LEDs start to come on at 7.5v when tested with a variable power supply. In my 1970 911T, the dimmer's voltage range is 9.3 to 12v, so they're pretty bright at the lowest setting. They get a bit brighter as the dimmer is turned clockwise, reaching 12v at the end of its range. This means that they never go off, that they vary between bright and very bright, which is fine for me.

OK, clear now. I also tested the voltage at the dimmer in the 87, that the car which dims the least. With Battery power only, I got 11V at the lowest and 12.1V with the dimmer full open. On this car is not much difference between low and high.

I got a 250 Ohm, 5W dimmer and connected it between the switch and the cable to the instrument lights. With the light switch dimmer full open I can now dim the LED's from complete off to bright, with a nice range.

Here is a video with the additional dimmer.

<iframe width="560" height="315" src="//www.youtube.com/embed/70znMNb0U0M" frameborder="0" allowfullscreen></iframe>

Cheers
Engelbert

So is the 5w dimmer a separate component with it's own dial/rheostat?

Looks like this dimmer has its own rheostat separate from the Porsche light switch rheostat, right?

Yes, it's a separate dimmer. Like I described in the post above, I connected it between the light switch and the cable that goes to the instrument lights.

Cheers
Engelbert

Correct !

Cheers
Engelbert

Do you sell this too? Can you post a pic of how it looks please?

I think your LEDs dim enough on there own, complete black out does not seem necessary :eek: at least for me.

There was a lot discussed about dimming, so I gave it a try and it worked great. I did not install the dimmer since I don't need to dim them down that much at this time. I just want to proof that it can be done, in case it's required.

I got the dimmer 250 Ohm, 5W from Didgikey. I can post the detail if needed.

Cheers
Engelbert

Perhaps a short wire extension with a fuse and the dimmer in line would be a nice upgrade for the instruments and also protect the instrument light circuit.

Please post the dimmer part number if you could.

LOL, funny how we are complaining about dimming the gauge lights down :rolleyes:

ain't that the damn truth.

Is this the one you got from Digikey?

http://www.jkllamps.com/pdfs/ZDM-01.pdf

Hi Porwolf, from the sounds of it Rothaus has just used a 250 Ohm 5W Potentiometer (variable resistor) to drop the volts fed to the illumination line that gangs all the LEDs together. I think I may try this alongside the in-line fuse.

Cheers, Neil

This is the dimmer I used from Didgikey p/n 026TB32R251B1B1 is $8

http://airboxer.com/images/dimmer.jpg


I was thinking making it in a package with pre-wired and mounting plate, but I think that there would be enough demand. So if someone want to dimm the LED's down like the standard bulbs, this dimmer can be used. You need also a knob, that's another $8 or so.

Hope this helps SmileWavy

Cheers
Engelbert

I did the same using a similar pot of 500 Ohm value. I also installed a 5A fuse in line with the pot. The result is bright to extremely dim from one end to the other of the adjustment. The variation isn't linear with the turning of the knob but it does work really well. There was already a hole in the dash that now has a nice black adjuster - very happy with the LEDs and being able to dim them.

Cheers, Neil

Make it stealthy non-intrusive bluetooth adjustable and I am sold :-).

I am just not diggin the idea of a secondary dimmer hardware. I have enough electrical components to worry about. My 2 cents.

There should be a rather simple electronic solution besides a PWM, to mimic the 500 ohm potentiometer regulating the LED current with the factory 5 ohm rheostat. Any ideas? I will think about some solution also.

Draco, that is cool. I had a grommet filled hole just below the Trip counter reset which was aching to be filled with something useful. The 2 wires go from the pot via a 5A fuse to be in line with the Blue/Black wiring just at/before the star point. No (new) holes in dash and no cutting/splicing of wiring. I can remove simply.

Cheers, Neil

I just purchase a set LED lights from Engelbert's website. I can't wait to get them install in my car.

Does anyone know of some good LED lights for the exterior lights, e.g. tail-lights, indicators, reverse...etc?

has anyone come up with plug and play LEDs for 964 & 993 yet?

mochaearth,

I bought "Philips (12899RX2) Red P21/5W LED Exterior Bulb" for the rear brake lights from Amazon. I also got a Hella LED third brake light from Daniel Stern. With so many people driving SUVs it's a good idea to get the third brake light closer to the eye level of the driver behind you.

I also got "1156-WHP28-T: Cool White" for the reverse lights from SuperBrightLEDs dot com. That was a huge upgrade.

The issue with the turn signals is you have to change the turn signal relay because of the lower voltage the LEDs draw.

still selling these LEDs?
 

I emailed Rothaus via his website and never heard back. Is he still selling these LEDs?

Yes, I still sell the LED's. When did you e-mail me ?

PM here, or post works also.

Cheers
Engelbert

Testing some Instrument LED
 

These are worth every penny, installed my set and very happy with them

Installed a set of the Vintage White, a marked improvement.

Thanks for the quick response.

I really need to do this. Currently at stage 3:

stage 1 research LEDs
stage 2 order LEDs
stage 3 leave on parts shelf for six months
stage 4 install LEDs
stage 5 post on here.

"I really need to do this. Currently at stage 3:

stage 1 research LEDs
stage 2 order LEDs
stage 3 leave on parts shelf for six months
stage 4 install LEDs
stage 5 post on here."

Oh, the number of projects that are at stage III. I honestly think there's a hidden time/urge sump located somewhere in my garage the causes this to happen. . .

Night....

http://forums.pelicanparts.com/uploa...1441466798.jpg

And Day... difference. Same camera, same lighting conditions, no flash on either one.

http://forums.pelicanparts.com/uploa...1441466846.jpg

I installed these several months ago but seeing this thread on the main page reminded me to post pics. I've driven at night and they aren't too bright but I think I'd go with the classic if I were to do it again. Money well spent all in all.

Can't we change the range of the factory POT with a parallel resistor?

Pro tip: don't put the beer fridge in the garage if you really intend to make progress :D

Ohhhh, I thought it was 6 years...I'm on step 3 but misread the rules.
I wish I was joking, but my project has been on hold for 6 years...time flies!
Time to motivate this winter and make some progress.

Rothaus,

Order placed for Vintage white with blue and green.

~Andy

Rothaus, I am interested in a set of Red LEDs with high beam indicator in blue and green TS indicators. Do you offer them, I didn't see them on your site. Thanks

I don't have them in RED, only Bright White and Vintage White. Sorry

The turning signal indicator bulbs are different, they are not BA7s. See below.

http://airboxer.com/images/SC-Carrera_Tach.jpg

Cheers
Engelbert

I bought a set of Engelbert's instrument LED's in vintage white. The install was very fast and the difference is amazing! Thanks Engelbert for a fine product!

BTW I don't think Engelbert sleeps....
He has a million projects going on at once and they are all making progress. :D

I put in an order for a set of these in bright white. Looking forward to getting them in.