LED Brake Lights

[spoke]

Originally Posted by Autoban

Spoke, just to verify before I place my order. Do I need to change to clear lenses on my '86 Carrera front turn signals to use the front turn signal LEDs with the daylight running lights? Going to LEDs for the front turn signal will not cause hyper-flash?

Juergen

Yes, if you want to use the white/amber front turnsignals, you need the clear lenses.

Yes, changing the front or rear or both turnsignals to LEDs will cause your flasher to hyperflash.

The flasher can be replaced by an EP26 or EP36 flasher found at your FLAPS or places like superbrightleds.com. Just make sure the description says "LED compatible" or similar as the EP26 number is an old number reused and some older EP26 flashers are out there and are not compatible with LEDs.

[Autoban]

Originally Posted by spoke

Yes, if you want to use the white/amber front turnsignals, you need the clear lenses.

Yes, changing the front or rear or both turnsignals to LEDs will cause your flasher to hyperflash.

The flasher can be replaced by an EP26 or EP36 flasher found at your FLAPS or places like superbrightleds.com. Just make sure the description says "LED compatible" or similar as the EP26 number is an old number reused and some older EP26 flashers are out there and are not compatible with LEDs.

Spoke, thanks for the quick reply. I will check into it since I really like the idea of having daylight running lights.

Juergen

[Autoban]

Originally Posted by spoke

Yes, if you want to use the white/amber front turnsignals, you need the clear lenses.

Yes, changing the front or rear or both turnsignals to LEDs will cause your flasher to hyperflash.

The flasher can be replaced by an EP26 or EP36 flasher found at your FLAPS or places like superbrightleds.com. Just make sure the description says "LED compatible" or similar as the EP26 number is an old number reused and some older EP26 flashers are out there and are not compatible with LEDs.

Spoke, a few more question. How are the daylight running lights powered? Do I need to run a separate wire for them? Will they turn off when the turn signal comes on to make the turn signal more visible?

Juergen

[69porsche]

Spoke,
Will your 911 Brake lights plug and play into a 1969-911 model year?
Gordon

[spoke]

Originally Posted by Autoban

Spoke, a few more question. How are the daylight running lights powered? Do I need to run a separate wire for them? Will they turn off when the turn signal comes on to make the turn signal more visible?

Juergen

Hi Juergen,

911's were configured with either a dual filament bulb (low output = running light; high output = turnsignal) or single filament turnsignal. See pic below.

If your bulb has 2 buttons like on the right, running light power is available in the socket. If your bulb is like on the left with a single filament; well, you have to be creative to get running light power to the board. The adjacent sidemarker fixture would have running light power and you would have to, well, again, be creative to either change the socket or adapt the wiring to accept running light power.

[spoke]

Originally Posted by 69porsche

Spoke,
Will your 911 Brake lights plug and play into a 1969-911 model year?
Gordon

Gordon,

The 911 brake light should work in the '69 911; I'm told. If you buy a set of brake lights and they don't fit, I'll take them back; no problem.

[spoke]

The saga of making LED brake lights compatible with cruise control continues...

Recall that I've added as much as 75 ohms of ballast onto my LED brake boards and still a couple of folks have seen issues with CC.

One Pelican member attached one of the off-the-shelf turnsignal ballast resistors (about 6 ohms; 50W) to the wires of an LED brake board with success. However, there's little room in the brake light cavity to add the resistor (it's big) and it will get hot with brakes continually applied.

Ideally the high power ballast resistor should be mounted where there's room and its heat won't bother anything. The brake light wire in the rear taillight fixture runs from the master cylinder to the CC ECU and to the taillight fixture.

What we're trying to do now is mount the ballast resistor in the front trunk by the MC and the brake light switch. Lots of room up front and no worries about the resistor heating up the LED board. (LEDs do not like heat)

This solution is being tested now.

Here's the brake light switch on MC.


Brake light switch plug. The black with yellow stripe goes to the CC ECU and the brake lights. This is the wire to add a ballast resistor.


This solution is a pigtail with 12 ohm ballast resistor. Pull the brake light plug off the switch and install this pigtail between the switch and the plug. The other end of the resistor will go to chassis ground.


Here's the pigtail connected between the plug and brake light switch. This will be tested in the next week or 2 so we'll know if it works.

[Canada Kev]

Does it matter which brake light switch it's wired to or do you do both of them?

[DRACO A5OG]

No it does not matter which one you use, it is a redundant system, There are two just in case once fails.

[spoke]

The pigtail with 12 ohms has been tested and is not quite compatible with the '89 911 cruise control. The CC seems to pick up the throttle but doesn't hold it. Will be trying another pigtail with 6 ohms.

With 12 ohm, the equivalent power is about 12W. With 6 ohm, the power will be about 24W which is consistent with the standard brake bulbs which burn about 21W.

[spoke]

When turnsignal bulbs are replaced by LEDs, many times the flasher relay must be changed because of incompatibility with low current LEDs. OEM flasher relays are generally designed to hyperflash at 2x the normal rate when a bulb burns out. This is a safety feature to alert the driver to the burned out bulb.

LED-compatible flasher relays like EP26 are readily available to replace the OEM units. The LED-compatible flashers will flash normally even with the low current LEDs although they do not have the capability to hyperflash should one of the LEDs burns out.

Porsche in their infinite wisdom designed the tachometer turnsignal indicators such that an auxiliary relay output on the flasher drives the common connection between the tach L & R indicators. The only pin-compatible and LED-compatible flasher I've found is the EP26. Unfortunately the 4th terminal (C or C2) of EP26 instead of driving the common connection, has no connection at all in the flasher.

In the next couple of posts, I'll detail what the flasher and tach indicator circuitry looks like in some early 911's and 914's, as well as how the circuit changes when EP26 is installed and a couple of work-arounds to the issue.

[spoke]

Here's the schematic for the '70-'73 914 flasher circuitry. Some years of 911 also use a similar setup for the left and right tachometer indicators. Notice the common connection of the dash indicators which connects to the "K" lead of the flasher. This is the 4th terminal of the flasher which LED-compatible EP26 flasher does not support.

In this circuit, when the turnsignal switch is set to L or R, the appropriate exterior lights are lit as well as the appropriate tach indicator.

Notice how the left tach indicator is connected to the right exterior bulbs and right indicator to the left exterior bulbs. As weird as this looks, I've verified this connection on several 914's when LEDs were installed.

[spoke]

Here's what a 911 flasher circuit may look like when LEDs are installed as exterior lights and EP26 flasher is installed. Notice the 4th terminal on EP26 called C2 is not connected to anything.

Now the common connection between the L and R tachometer indicators is not driven at all. So basically now we have the L and R tach indicators in series connected between the exterior left and right LEDs.

What would we see in operation in this case? Let's assume the right turnsignals are selected. The right exterior LEDs would flash normally as expected.

However, the 2 tach indicator bulbs in series would have 12V on one side and the left exterior LEDs on the other side. As the right side LEDs flashed normally, the left exterior LEDs would flash very lightly as would both L and R tach indicators will flash gently.

The center connection between the L and R tach indicators must be corrected for proper operation. In the next posts, I'll show how this can be fixed.

[spoke]

With EP26 installed, the C2 spade on EP26 is not connected to anything. We need to make an external connection to solve this issue.

Again, not all 911 models are connected like this. My '86 930 does not use the C2 terminal so I did not have to do this mod.

To fix this, the common wire to the L and R tach indicators is removed and taped off.

A 3 way pigtail like shown in the pic below is connected as shown in red on the schematic. The ground connection is found on the tach itself. This will solve the L and R indicator flashing properly as well as keeping the other side's exterior LEDs from "ghosting".



3-way pigtail to connect to the common connection of the L and R tach indicators.



Here's the 3-way pigtail connected on a 914 tach.

[spoke]

An alternate way to ground the common connection of the L and R dash indicators is to modify the EP26 C2 lead to connect it to ground inside the unit. I've modified a couple of EP26's for some folks for their 914's.

[spoke]

The front turnsignal bucket for '69-'73 911's are different from the '74-'89 cars. I designed a board for the early cars using an aftermarket bucket. The unevenness of the cavity opening required different size pinch clips between the front and rear of the PCB.

I now have an OEM bucket from another Pelican member to check fitment of the PCB. Here's the OEM bucket, the LED PCB, and the position frame to properly position the board in the bucket.

For the board to fit, I had to remove the metal divider near the inside of the bucket.



The position frame fits well so no mods needed on it.



The PCB fits ok but the OEM bucket is a little narrower than the aftermarket unit. The inside pinch clips need to be smaller to fit better. One can see towards the left side of the board how much more space there is than the right side. As before, it looks like I'll have to send several sets of different size pinch clips to accommodate the bucket width differences.

[spoke]

Originally Posted by areanence

That looks great to me! I assume some of the leds are on for tail, and all on for stop? Or they all on but dimmer?

For front amber turnsignals, rear RED turnsignals, and brake boards, the LEDs operate at 2 levels as you mention: dim for running lights and bright for turnsignal/brake.

How are you connected to the original socket? A double pole one/way bulb base?

I buy empty BAY15D and BA15S bulb bases and print inserts to ease soldering and installation by adding a handle.

Something like this is readily available, but yours looks to fit the 911 reflector aperture exactly - very nice.

What product are you referring to? I'm curious about what is available.

I try to design the largest board possible and install the most LEDs that will fit and not get hot with use.

How much for a set?

For the '69-'73 front turnsignals, if all amber LEDs, price is $125. For white/amber LEDs where the white running lights are turned off when the turnsignal is active, price will be $145.

When I redesign this board (I only ordered 6 boards for the prototype build) it will be designed to accept white LEDs for running lights on some of the LEDs. Question right now is whether folks would want a line of white LEDs (actually 2 rows with 12 LEDs per row) or all white LEDs bunched on one side of the board.

If white running lights are desired, one would have to buy what Pelican calls "Italian" lenses like below.



If all the white LEDs are bunched up on the end of the PCB, then the "European" lenses could be used.

[boxcarracer]

Installed the rear turn signal boards and am taking current from the rear position led as you mentioned. Looks great, well thought out and now my whole rear end is lit with LEDs ��

[john baldwin]

Post 547 shows the resistor/ pigtail assembly Jerry fabricated to address the inoperable cruise control on later model Carrera's. Very clean, no cutting, installs between the male/ female plugs of the brake light/ master cylinder...a 5-minute job.

Jerry sent me that 12-ohm version to try...the cruise tried to engage but then couldn't hold the setting. He then followed up with a 6-ohm version and all is well. Holds up and down hills, disengages with both the lever and brake pedal and the car will resume speed by pushing the lever down.

What's more impressive to me than this elegant solution is the customer service I received. Jerry and I exchanged several PM's/ emails with all my questions and pictures patiently and enthusiastically answered. When I sent him a link to the resistor assembly I was considering, he emailed me back saying he was sending me the pigtail assembly! I had no expectation of that whatsoever...

So if you're on the fence about these LED lights, don't be. Jerry wants to see satisfied customers and is more than happy to help guide us through any difficulty. Such customer service is a rarity these days.

Kudo's Spoke!!!

[422flat6]

Spoke,
I plan to buy a set from you after I get some higher priority issues taken care of. Definitely would want the 69-73 fronts to be compatible with the euro lenses. The Italian lenses look weird to me.