side marker won't flash with turn signal

Normal flasher cans don't work with LEDs. Some electronic flashers can be modified, though I suspect new flashers are simply pulsing relays without any current sensing (hence not letting you know that a bulb is faulty). If you use LEDs in line with incandescents, then the LEDs will flash or turn on instead of the incas - and incandescent will not illuminate (brightly) if in series with LEDs - unless it is a big LED array (with similar or greater current to the inca bulbs). So if you do not have the same bulbs & LED placement as the cars that work, your lighting will not work the same.

I just discovered that the other person who this mod works on has both a flasher for LED and LED turn signals as well *I have a normal bulb* I was wondering which one I should try first to see if it works....a new flasher or LED....

So I changed out my flasher, and it works! but only if I have the regular incandescants for the side markers and the turn signal. Im guessing I can't mix and match? Would LED turn signals and LED side markers work since they are same current?