By Barry Lee Brisco
By modern standards, stock 356 brake lights and rear running lights are weak: difficult to see during the day, not particularly bright at night, and placed rather low. Today's drivers are used to very bright rear lights placed three to four feet above the road surface, and it's entirely possible they may not even notice your 356 brake lights when you really need them to. The unhappy result of their inattention could be a crunched rear end or even a totaled 356.
Happily, there is a solution to this problem. LED array lights are now available in several forms and offer significantly greater brightness than incandescent bulbs. LED bulbs that simply plug into the 356 taillight assembly sockets can be found in both 6V and 12V, for either BA15s (teardrop) or BA15d (beehive) socket types ,and they generate no heat. To my eye these bulbs appear to be about twice as bright as the stock bulb. They work fine with the stock flasher relay (no need to change to a modern electronic flasher), the turn signal blink rate appears unchanged, and when lit the illumination pattern looks the same as the stock bulbs. Even with a retail price of around US$45, for the extra safety it's a small price to pay, and they will likely last beyond the lifetime of your 356! (sources listed below). Note: the owner of a 356C 6volt car has reported that after installing LED taillights they did not see any noticeable increase in brightness, and they stuck with the standard bulbs. Other owners have been satisfied with the improvement from these LED bulbs.
Besides the increased brightness, another advantage of any LED unit is they come on instantly when the brakes are applied. Incandescent bulbs take a brief period of time (some people say about 0.2 seconds) to achieve full brightness. But at 70 mph, 0.2 seconds equals about 20 ft. So having LED taillights in a 356 is like putting another 20 ft. of distance behind you in terms of the reaction time of the driver following you. When the 356 driver with LED taillights applies his brakes, in essence the driver behind sees the brake lights 20 ft. "earlier" (at highway speeds) as compared to incandescent bulbs.
36 LEDs per side for your 356
In January 2008 a new product was announced by Cu Layer, a circuit board design company owned by long time 356 enthusiast Jim Franzen. His "Model 356 LED Taillight System" uses a custom made teardrop-shaped circuit board with 36 high intensity rear-facing LEDs that replace both the running light and the brake/turn signal light, all in one unit (see photo at right). It installs in just a few minutes and requires no modifications to the car. It is available in either red or amber for the brake light side for 6 volt or 12 volt cars (no "beehive" type LEDs from this company...yet). Based on my testing, the unit works fine with the old flasher relay in my car but I don't think it is an original stock relay. However, it is not a new electronic relay.
According to the manufacturer, the units are built in such a way that a single LED failure will not cause all the LEDs to go dark. Each unit employs three voltage regulators to ensure maximum brightness regardless of voltage variations, and if one of the two brake light regulators fail only half the brake LEDs are affected. The circuitry is also protected against electrical transients.
The improvement in luminosity is dramatically greater than the other individual LED bulbs I am familiar with because all the LEDs in the Cu Layer design face to the rear and there are so many more of them. See the comparison photos shown below. Since the circuit board is in the same plane as the taillight assembly, which is turned slightly to the side due to the 356 body design, maximal brightness is slightly off-axis. Priced at $179 for a pair, they are more costly than a pair of individual LED "plug in" units but are about the same as four of them, as they replace not only both brake lights but also both running lights. In my opinion the only real negative is that when lit they do not appear "vintage": the pattern of the LED array is visible, though of course when they're off the LED board cannot be seen through the taillight lens. I consider this a very minor downside compared to the upside, which is significantly greater visibility not only at night but also during the day. Finally I feel that my brake lights and rear turn signals can be clearly seen even when the sun is shining. With the usual incandescent bulbs, 356 taillights are almost invisible during the day.
The photos shown below compare the Cu Layer unit with incandescent bulbs and the individual LED bulb arrays. This is not a scientific test, simply a series of photos taken at night with the flash off (except for the last image) and the exposure settings kept constant. They are consistent with what my eyes were telling me: the Cu Layer units offer the brightest rear lighting I've ever seen from a 356 teardrop taillight assembly.
Running Light Comparison: Cu Layer LED vs. Incandescent
Driver side: Cu Layer LED taillight — Passenger side: 10w incandescent bulb
Brake and Running Light Comparison: Cu Layer LED vs. Incandescent
Driver side: Cu Layer LED taillight — Passenger side: 10w incandescent running light and 18w incandescent brake light
Brake and Running Light Comparison: Cu Layer LED vs. NLA LED
Driver side: Cu Layer LED taillight — Passenger side: 10w incandescent running light and NLA LED brake light
Cu Layer LED taillights both sides (taken with flash on to show the LED array pattern)
This list of vendors, in alphabetical order, is not necessarily comprehensive, and additional companies may also offer similar products. Note that where possible, links are provided directly to a specific product page if available.
Cu Layer: Model 356 LED Taillight System
Elevenparts (Europe): LED brake light
NLA: LED lights