When changing to LED turnsignals, the OEM flasher may hyperflash at 2x the normal rate, and the tachometer turnsignal indicators may not flash or flash together.
 
If either happens, you need to replace the flasher with EP26. EP26 LED-compatible flashers by Novita/Tridon do not activate the C2 pin which Porsche uses to power the tach turnsignal single indicator for the 74-76 914.
 
This EP26 module is modified to connect pin C2 to 12V when flashing so the single tach turnsignal indicator works properly.