Making Your Flasher Relay LED Compatible |
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Making Your Flasher Relay LED Compatible |
Spoke |
Dec 31 2015, 08:43 AM
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#1
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Jerry Group: Members Posts: 7,084 Joined: 29-October 04 From: Allentown, PA Member No.: 3,031 Region Association: None |
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 |
Jan 1 2016, 06:33 PM
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#2
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Jerry Group: Members Posts: 7,084 Joined: 29-October 04 From: Allentown, PA Member No.: 3,031 Region Association: None |
'74+ 914 with single L/R dash indicator.
This flasher is an issue when changing to LED turnsignals. Notice the schematic below where the 4th terminal on the flasher relay is called C or C2. The C/C2 terminal is energized again with a second relay. The relay will pull in only when the heavy current of at least 2 turnsignal bulbs (front and rear) and flash the L/R indicator. When the brake warning light is on, the bulb passes very low current and will not pull in the second relay and will not flash the L/R dash indicator. When changing to LED turnsignals, the current from the turnsignals is now very low compared to the standard bulbs. Thus the second relay will not pull in and the L/R dash indicator will not flash with the turnsignals. There is no easy solution to fix this. The EP26 is pin-compatible but the small sample of EP26's I've looked, the C/C2 terminal was not connected to anything. There are a couple of solutions although neither are simple. The first solution is to change tach bodies from late tach to early tach. I did this in my '74 but I did it to get the separate L and R indicators. I really don't like the single L/R indicator. I swapped out the tach guts so all I used was the tach body. Another solution is to take the EP26 apart and wire the C/C2 to power the terminal when the relay flashes. The downside of this approach is the single L/R dash indicator will flash even when the brake warning light is active. Another solution is to power the single dash indicator from the L and R turnsignal wires. 2 diodes would be needed to isolate the L and R turnsignals from each other. The standard flasher can be used in this case. So for this configuration, there is no easy, simple answer. Any ideas on solutions would be greatly appreciated. |
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