i looked up the destructions to an eps unit on cj pony, it says you use a 60 amp fuse. that's a lot of current. it's possible it's drawing so much juice, that the old mechanical flasher isn't heating up enough to trip the lights on and off. make sure you replaced the correct flasher, not the one for the four ways, and then try a electronic flasher instead of the stock mechanical type. also check to see if your stock alternator even puts out enough current to run the eps unit, you may have to upgrade