996 LED Install

[Dwiggy]

After a long decision to change all of my factory lights out with LEDs I came across a small dilemma. The tail and brake lights share an 1157 dual filament bulb. When installing the 1157 bulb the tail and brake lights would not work independently. I pulled out my multi meter and discovered that all of the light circuits in the Porsche are negative reference. Effectively this means that when a light is turned off its positive lead returns to ground.

On 1157 LEDs the two stage brightness is accomplished through two series of resistors attached to the same circuit of LEDs. When 12v is connected to one lead the light is brighter then the other lead, however they are interconnected.

When the tail light is turned on a 12v signal is sent to one of the 1157 leads (for low intensity). However if the brake is not depressed, the other lead (for high intensity) is grounded as well. The grounded lead negates the circuit and the light will not operate. There is a solution through the use of two more diodes. I have attached pictures to visually explain the install process.

As a final note, the diodes are directional, make sure to install them with the silver stripe towards the socket as I have.

D.

Edited October 25, 2009 by Dwiggy

[Dwiggy]

In addition to the 1157 delima there is one more note I should add. If you are not familiar with LED turn signal installations this is a must read. The factory turn signal flasher requires a certain load to operate at normal timing. LEDs require about a 10th of the current that OEM bulbs require and this causes your lights to flash as if a bulb were out (rapidly). It is very simple to fix this problem by simply replacing the factory relay with an LED relay. Here is a picture of the parts required for the turnsignal instal.

Take note that the rear bulbs are 7507s while the fronts are 7506s. It is easy to find the amber 7506 bulbs as they are a standard 1156 single element replacement. However, not all suppliers have the 7507 LEDs which have a different bayonet connector.

I also attached a picture of my OEM rear turn signal bulb with the orange paint falling off.

Edited October 25, 2009 by Dwiggy

[Dwiggy]

Here is a complete parts list for the LED replacement for a 1999 - 2001 PORSCHE 911

Parking light

OEM: 2825

LED: Cool White (Color optional for fun) WLED-x6 LED bulb 3.74 ea / 2 req. 7.48 Total

High mount stop light

OEM: 2821

LED: WLED-Red-x LED bulb .79 ea / 14 req. 11.06 Total

Front side marker

OEM: 2825

LED: WLED-Amber-x LED bulb .79 ea / 2 req. 1.58 Total

Step/Courtesy light/ Map Lights

OEM: 2825

LED: Cool White (Color optional for fun) WLED-x6 LED bulb 3.74 ea / 4 req. 14.96 Total

Front turn signal

OEM: 7506

LED: 1156 Amber BA15 24-LED bulb 7.49 ea / 2 req. 14.98 Total

Tail light/Stop Light

OEM: 7528

LED: Red 1157 BA15 24-LED bulb 7.49 ea / 2 req. 14.98 Total

Back up light

OEM: 7506

LED: 1156-W12 White Wide View LED bulb 6.99 ea / 2 req. 13.98 Total

Rear turn signal

OEM: 7507

LED: PY21W offset 24 LED (Amber) Indicator Bulbs 10.79 pair/Total (Auction)

License plate

OEM: 6418

LED: Cool White 3610-x4 LED Festoon bulb 2.84 ea / 2 req. 5.68 Total

Dome light/Cargo Area/Under Hood

OEM: 6411

LED: Cool White 4410-x9 LED Festoon bulb 4.74 ea / 3 req. 14.22 Total

Tail/Stop Light Diodes

2 x 3A 1N5404 barrel diodes 1.59 ea / 2 req. 3.18 Total (Radio Shack)

Turn Signal Relay

LED bulb Flasher Unit CF13 GL-02 12.95 ea / Total

This is a total of 125.84 for all of the parts listed. If you do some shopping around you can find the small WLEDs for less in bundles and so on. Over all it is a cool upgrade with modern technology.

Some things to consider are that LEDs are not as bright as conventional incandescent bulbs unless viewed directly. However, LEDs do require less current and because of this have virtually undetectable radiant heat. If one where to calculate the total current draw from the LED (v) incandescent circuits he or she would discover a significant drop in overall battery usage. Therefore all electrical circuits and components will get less wear and tear throughout the years.

As a final note, the diodes selected for the 1157 install where chosen because they are large enough to use with the factory incandescent light bulbs if needed in a pinch when LED replacements are not available. When installing diodes, cover all exposed terminals and attempt to seal them from submersion. Do not cover the complete body of the epoxy diode as some minor heat dispersion will ensure a component longevity.

References

www.radioshack.com

www.eBay.com

www.superbrightleds.com

* Most of the listed prices are from superbrightleds.com. This post may not be misconstrued as an advertisement for eBay Motors, Radio Shack or Super Bright LEDs. This poster is in no way affiliated with any of the parts vendors referenced in this forum. Finally by posting this discussion, I am by no means responsible for how viewers use this content.

Edited October 25, 2009 by Dwiggy

[Dwiggy]

I apologize, I forgot about the rear fog light.

Rear Fog Lamp

OEM: 7506

LED: 1156 Red BA15 24-LED bulb 7.49 ea / Total

You can install two of these bulbs (one on each side) but it is not necessary. The factory configuration has two sockets but there is only a bulb on the driver's side of the car.

Make that new total 133.33.

D.

[goldenwarrior1]

I apologize, I forgot about the rear fog light.

Rear Fog Lamp

OEM: 7506

LED: 1156 Red BA15 24-LED bulb 7.49 ea / Total

You can install two of these bulbs (one on each side) but it is not necessary. The factory configuration has two sockets but there is only a bulb on the driver's side of the car.

Make that new total 133.33.

D.

Dwiggy,

Can you post pics when you are done? Would like to see a picture of the lights "lit" at night. Curious as to the difference between OEM and the LED's.

Thanks, GW

[Dwiggy]

I apologize, I forgot about the rear fog light.

Rear Fog Lamp

OEM: 7506

LED: 1156 Red BA15 24-LED bulb 7.49 ea / Total

You can install two of these bulbs (one on each side) but it is not necessary. The factory configuration has two sockets but there is only a bulb on the driver's side of the car.

Make that new total 133.33.

D.

Dwiggy,

Can you post pics when you are done? Would like to see a picture of the lights "lit" at night. Curious as to the difference between OEM and the LED's.

Thanks, GW

Here are the LEDs installed. I took pictures of the tails, the parks, side markers, hazards, maps and step lights.

I used a xenon color for the interior and the park lights.

What you cannot see in pictures is the clarity of these lights. The interior has a nice cool look. The turns and brakes are on and off instantly. There is no delay in LEDs.

D.

[wwest]

Most LED bulbs have an internal fullwave bridge rectifier that negates this problem.

[Dwiggy]

Most LED bulbs have an internal fullwave bridge rectifier that negates this problem.

That would work really well on AC... ;)

D.

[goldenwarrior1]

I apologize, I forgot about the rear fog light.

Rear Fog Lamp

OEM: 7506

LED: 1156 Red BA15 24-LED bulb 7.49 ea / Total

You can install two of these bulbs (one on each side) but it is not necessary. The factory configuration has two sockets but there is only a bulb on the driver's side of the car.

Make that new total 133.33.

D.

Dwiggy,

Can you post pics when you are done? Would like to see a picture of the lights "lit" at night. Curious as to the difference between OEM and the LED's.

Thanks, GW

Here are the LEDs installed. I took pictures of the tails, the parks, side markers, hazards, maps and step lights.

I used a xenon color for the interior and the park lights.

What you cannot see in pictures is the clarity of these lights. The interior has a nice cool look. The turns and brakes are on and off instantly. There is no delay in LEDs.

D.

Thanks Dwiggy,

Hard to appreciate the full effect from a photo but they look much brighter. I especially like the interior lights! Thanks for taking the time to post your efforts and final results.

GW

[wwest]

Most LED bulbs have an internal fullwave bridge rectifier that negates this problem.

That would work really well on AC... ;)

D.

It also works well to make the LED bulb non-polarity sensitive, as in the above case.

[1schoir]

Dwiggy:

Thanks for taking the time to write this up, especially with all of the part numbers, etc... :clapping:

Will save lots of time and aggravation for anyone wanting this mod.

I'd like to see one in person before I dive in!

Regards, Maurice.

[phillipj]

Dwiggy,

You did an awesome job. Maybe when we meet you can tell me about how I could change my interior lights to Xenon color. That is so cool. B)

Thanks for the write up! Great job! :clapping:

:cheers:

[Dwiggy]

Most LED bulbs have an internal fullwave bridge rectifier that negates this problem.

That would work really well on AC... ;)

D.

It also works well to make the LED bulb non-polarity sensitive, as in the above case.

Thanks for the update W. :)

I thought that a rectifier bridge was used to change AC to DC by stripping off half of the wave... but I guess what you are saying does make sense even though I wish I knew where to shop for the right LEDs. I figured they were all made the same.

When I spoke to superbrightleds about this problem they did not have a solution and did not know of the issue entirely. Maybe I bought cheap 1157 LEDs as I found mine on eBay...

In either case if it is not too much trouble can you send a schematic for a full wave bridge rectifier that you describe. I am somewhat familiar with circuitry but I need a visual to understand it entirely. I would like to compare your schematic to the actual 1157 LED schematics for future reference.

Thanks again,

D.

[Dwiggy]

Dwiggy,

You did an awesome job. Maybe when we meet you can tell me about how I could change my interior lights to Xenon color. That is so cool. B)

Thanks for the write up! Great job! :clapping:

:cheers:

No problem on the 996 I'm sure the 997 is just as easy...

I bought a ten pack of xenon colored WLEDs for 10 dollars off of eBay and then started plugging them into everything! :D

Thanks for the compliments :) This forum stuff is fun.

D.

[wwest]

Most LED bulbs have an internal fullwave bridge rectifier that negates this problem.

That would work really well on AC... ;)

D.

It also works well to make the LED bulb non-polarity sensitive, as in the above case.

Thanks for the update W. :)

I thought that a rectifier bridge was used to change AC to DC by stripping off half of the wave... but I guess what you are saying does make sense even though I wish I knew where to shop for the right LEDs. I figured they were all made the same.

When I spoke to superbrightleds about this problem they did not have a solution and did not know of the issue entirely. Maybe I bought cheap 1157 LEDs as I found mine on eBay...

In either case if it is not too much trouble can you send a schematic for a full wave bridge rectifier that you describe. I am somewhat familiar with circuitry but I need a visual to understand it entirely. I would like to compare your schematic to the actual 1157 LED schematics for future reference.

Thanks again,

D.

V-LEDs on ebay.

[Dwiggy]

Most LED bulbs have an internal fullwave bridge rectifier that negates this problem.

That would work really well on AC... ;)

D.

It also works well to make the LED bulb non-polarity sensitive, as in the above case.

Thanks for the update W. :)

I thought that a rectifier bridge was used to change AC to DC by stripping off half of the wave... but I guess what you are saying does make sense even though I wish I knew where to shop for the right LEDs. I figured they were all made the same.

When I spoke to superbrightleds about this problem they did not have a solution and did not know of the issue entirely. Maybe I bought cheap 1157 LEDs as I found mine on eBay...

In either case if it is not too much trouble can you send a schematic for a full wave bridge rectifier that you describe. I am somewhat familiar with circuitry but I need a visual to understand it entirely. I would like to compare your schematic to the actual 1157 LED schematics for future reference.

Thanks again,

D.

V-LEDs on ebay.

Thanks I checked out V_LEDs and they make a premium product, deffinately the way to go but very costly. They're 1157s are actually electrically isolated. I did some researching and it looks like the bridge rectifier is actually used to direct current in one way so the bulb is not polarity sensitive.

D.

[JeTexas]

I just visited the V_Led.com site and filled a cart with all the bulbs on your list. It was $371.39 before shipping.

Why are the V_Leds so much more expensive than the Superbrights? What difference am I going to see in the $7 pair of lights versus the $49 pair of lights?

[Dwiggy]

I just visited the V_Led.com site and filled a cart with all the bulbs on your list. It was $371.39 before shipping.

Why are the V_Leds so much more expensive than the Superbrights? What difference am I going to see in the $7 pair of lights versus the $49 pair of lights?

Let us know if you purchase them.

From Superbrightleds.com the 1156 and 1157 LEDs are not near as bright as the OEM bulbs. The peanut sized bulbs are just as bright if not brighter.

Also, from what I have read about the V LEDs thier 1157s are actually isolated circuits. They have multiple color LEDs for turn and tail light applications. All in all the V LEDs look to be the way to go but at a premium price.

D.

[wwest]

Just finished a complete LED exterior update/retrofit for our 1988 Carrera SE.

1. Dual color 1157, HID/white parking/marker mode, amber turn signal mode, $25.00/pair, ebay seller para2386.

2. Red 1157, rear tail/stop, $30.00/pair, ebay seller peraccurate.

3. Red 1156, rear turn, $30.00/pair ebay seller peraccurate.

4. "HID"/White 1895, rear marker/parking, $14.00/pair, V-LEDs.

5. "HID"/White 1895 "Flank", front marker, $14.00/pair, V-LEDs.

[wwest]

In addition to the 1157 delima there is one more note I should add. If you are not familiar with LED turn signal installations this is a must read. The factory turn signal flasher requires a certain load to operate at normal timing. LEDs require about a 10th of the current that OEM bulbs require and this causes your lights to flash as if a bulb were out (rapidly). It is very simple to fix this problem by simply replacing the factory relay with an LED relay. Here is a picture of the parts required for the turnsignal instal.

Take note that the rear bulbs are 7507s while the fronts are 7506s. It is easy to find the amber 7506 bulbs as they are a standard 1156 single element replacement. However, not all suppliers have the 7507 LEDs which have a different bayonet connector.

I also attached a picture of my OEM rear turn signal bulb with the orange paint falling off.

Your other choice was to pop the cover off of the flasher relay and replace the nichrome current sensing link with a 0.5 ohm 5 watt resistor. 5 watts is not needed unless you have need to temporarily install an actual incandescent at some time in the future.

The nichrome link is designed to drop >100 millivolts at 3.5 amps. The two LED bulbs will draw only 200-300 milliamps so the 0.5 ohm resistor should suffice. With 1 LED bulb "failed" you will then still get "fast flash" as an indicator.

[kristian]

I bought some LED lights for my car about a year ago, but I had some problems too and I decided not to install them. I only installed the tail corner lights. I installed the brake light, but it was not as bright as the original, so I did not do it. I replaced my 3rd brake light with a clear unit that I bought from Ebay wihtout having do do any modifications. I also liked the clear look more than the original read

KL

[ChrisJP]

Just bought 2 BSLE13 LED for the brakelight http://en.item.rakuten.com/caraz2/bsle13/ and none would light-up.

I tried to rotate them 180deg, change position to other BA15S receptacle, but it won't work.

What did I miss?

[ChrisJP]

Just realized how stupid I was trying to reverse polarity by turning the led 180deg :oops:

I checked the leds with a battery and they work fine.

The + is at the bottom of the LED : is that the correct polarity for the brake light of a 02 Boxster?

Or should I get LED with reversed polarity (- on the bottom)?

[wyovino]

Wouldn't white LED lights be better for brake lights and tail lights since the lens is red?

[ChrisJP]

While looking for leds, I read that a "colored lens will filter out all but the colored portion of the light"

So my lens being red, I'm using red led so that a "smaller amount of light will be blocked by the lens".

Here is the reference: http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=%2Fcarbulb-notes.htm

As to why the led doesn't work, I suspect that it is a polarity issue but I'm still waiting for a confirmation from the forum (I don't have voltmeter).

Edited January 2, 2011 by ChrisJP