Flysky and Relay

I tried this and only one side works

  if (sig1 > 1800)
    armrobot = HIGH;
  else if (sig1 < 1200)
    armrobot = LOW;

  if (sig6 < 900)
    plowup = HIGH;
  else if ((sig6 < 1400)&&(sig6 >1500))
    plowup = LOW;

**if (sig6 > 1800)**
**    plowdown = HIGH;**
** else if ((sig6 > 1400)&&(sig6 <1500))**
**    plowdown = LOW;**

only the down (Bold) works