My EP35 LED flasher works just fine with my switchbacks? I dont know why you are having a problem? Get the EP35 from autozone if it isnt the one you are using.
Check your wiring to just in case. The switchbacks are touchy.
i went to 2 autozones and they didnt have a ep35 led relay they said that its one of the things that they are cutting down in stores and is a website only thing but going on their website i didnt find it on there