Making Your Flasher Relay LED Compatible Options

[Spoke]

This thread is meant to help those implementing LED turnsignals on their 914.

Standard flasher relays were designed to flash 2 standard bulbs (21W each) for turnsignals or 4 standard bulbs with 4-ways on.

LED replacements burn between 2W and 5W and electrically may not behave at all like a standard bulb. The LED replacements can cause all kinds of weird things like hyperflash (2x normal flash rate), dash indicators do not work, or the the flasher relay does nothing at all.

The 914 flasher is different for early cars 70-73 than later 74+ mainly because of the tach indicators. Early cars have individual L and R indicators and the 74+ have a single L+R indicator. Both are handled differently by the flasher.

There are LED-compatible flashers generally available at your FLAPS which are plug-in but not totally function compatible with the 914 standard flasher. The functional issue revolves around the 4th terminal which the 914 uses to activate the dash indicators.

The aftermarket flasher relays are EP26 (4 terminal) and EP36 (3 terminal). I've seen these at Pep Boys, Autozone, and Advance Auto to name a few FLAPS, usually for less than $15.

I'll detail the differences between early and late cars, as well as EP26 and EP36 in the next few posts.

[Spoke]

'70-'73 914 with separate L and R dash indicators. This arrangement is pretty straightforward and likely can work with the standard 914 flasher relay with a modification of the dash indicator common wire.

Below is a generalized schematic of the turnsignal system. Look at the flasher relay in the top right corner. It has 4 terminals:
49: This is power into the relay
49a: This is output to the turnsignal bulbs
31: Ground
K: This pin drives the common wire to the the dash indicators.

The flasher has dual purpose. It flashes the turnsignals and if the MC warning switch or E-brake switch is closed, will flash the brake warning dash indicator.

Notice the K lead on the flasher goes through a second relay contact. The K lead is only active if a large current flows through 49a. This way it is active if turnsignals are being driven (like 40W or so) and inactive if a light load like the brake warning light is driving 49a.

I will say here that connection of the K lead in the flasher below may not be correct. It may connect the K to ground. If someone has an extra flasher relay with the K lead and it works, I would gladly purchase it from you so I can test it.

This flasher does not hyperflash as it is designed to flash normally for turnsignals (heavy load) and brake warning light (light load).

The K lead is the one which causes problems. In general, over the years the second relay weakens such that it stops driving K and when either turnsignal is on, both flash at 1/2 brightness. When LEDs replace the standard exterior turnsignal bulbs, the lower current of the LEDs may not pull in the second relay and K will not drive the dash indicators.

The solution to the K lead is to remove the common connection at the dash indicators and replace the wiring with a small Y pigtail like below. The removed common connection should be taped up so it doesn't contact anything.

The K lead is not used at all. If the standard flasher works, there is no need to change it. If it doesn't work correctly with LED turnsignals, it can be replaced by the EP36. EP36 has 49, 49a, and 31 terminals and is plug-in compatible.



This pigtail connects both dash indicators to ground thus not using the K lead at all.



Ground lead sharing the ground (brown wire) of the tach. I have been including a 1:2 spade with turnsignal boards for a while. You would have to source the Y cable yourself.