He probado cambiando simplemente el ejemplo del led 13 y no hace nada...
/*
Blink
Turns on an LED on for one second, then off for one second, repeatedly.
This example code is in the public domain.
*/
void setup() {
// initialize the digital pin as an output.
// Pin 13 has an LED connected on most Arduino boards:
pinMode(A5, OUTPUT);
}
void loop() {
digitalWrite(A5, HIGH); // set the LED on
delay(1000); // wait for a second
digitalWrite(A5, LOW); // set the LED off
delay(1000); // wait for a second
}