Another LED bulb question

[forestb]

Whatever led bulb I try to install on the front turn signals it never works. If I turn on the blinker it just stays lit and the rears (led) don’t blink at all. I have the special blinker switch. It works fine if I have the leds in the rear and normal bulb up front. I have cleaned off all the metal to metal connections so I am pretty sure it is well grounded. Is there another way to ground it that I am missing? It’s a 62 c10 pickup.