limit switch problem

[krudeboy51]

After 16 hour of working on two limit switches, they still won't work. I wrote a code for our limit switches that when our top limitswitch is pressed it would stop the motor from going up so the motor can only go down, and when the bottom one is pressed it stops the motor from going down so the motor can only go up. The problem is that I does not do any of that. Can any one please review this code an tell me where I went wrong?

		    if (ds->GetDigitalIn(3) != 1 || ds->GetDigitalIn(3) != 1 && Carriage_down->Get() == 0)
		    {			    
			    Carriage_motor->Set(1.0);
			    while(Carriage_down->Get() == 0)
			    {
			    	Carriage_motor->Set(0.0);
			    }
		    }
		    else if(ds->GetDigitalIn(4) != 1 || ds->GetDigitalIn(4) != 1 && Carriage_up->Get() == 0)
		    {
		    	Carriage_motor->Set(-1.0);
			    while(Carriage_up->Get() == 0)
			    {
			    	Carriage_motor->Set(0.0);
			    }
		    }
		    else
		    {
		      	Carriage_motor->Set(0.0);
		    }