Use a voltmeter at the connector on the BCM, If both are high, the wing is between "UP" and "DOWN" or if it is UP or DOWN, then that limit switch is bad.
If both are low, I'd suspect a loss of bias from the BCM, altho it could be that both wires are shorted to ground somewhere, altho I doubt that.

Of course, once in a while, it's the MOTOR that has simply failed. Measuring for power going to the motor when the button is pressed will reveal that.