diff --git a/ArduCopter/leds.pde b/ArduCopter/leds.pde
index dd7a584bcc..8f1d82de03 100644
--- a/ArduCopter/leds.pde
+++ b/ArduCopter/leds.pde
@@ -19,23 +19,23 @@ static void update_GPS_light(void)
 	switch (g_gps->status()){
 
 		case(2):
-			digitalWrite(C_LED_PIN, HIGH);  //Turn LED C on when gps has valid fix.
+			digitalWrite(C_LED_PIN, LED_ON);  //Turn LED C on when gps has valid fix.
 			break;
 
 		case(1):
 			if (g_gps->valid_read == true){
 				GPS_light = !GPS_light; // Toggle light on and off to indicate gps messages being received, but no GPS fix lock
 				if (GPS_light){
-					digitalWrite(C_LED_PIN, LOW);
+					digitalWrite(C_LED_PIN, LED_OFF);
 				}else{
-					digitalWrite(C_LED_PIN, HIGH);
+					digitalWrite(C_LED_PIN, LED_ON);
 				}
 				g_gps->valid_read = false;
 			}
 			break;
 
 		default:
-			digitalWrite(C_LED_PIN, LOW);
+			digitalWrite(C_LED_PIN, LED_OFF);
 			break;
 	}
 }
@@ -47,14 +47,14 @@ static void update_motor_light(void)
 
 		// blink
 		if(motor_light){
-			digitalWrite(A_LED_PIN, HIGH);
+			digitalWrite(A_LED_PIN, LED_ON);
 		}else{
-			digitalWrite(A_LED_PIN, LOW);
+			digitalWrite(A_LED_PIN, LED_OFF);
 		}
 	}else{
 		if(!motor_light){
 			motor_light = true;
-			digitalWrite(A_LED_PIN, HIGH);
+			digitalWrite(A_LED_PIN, LED_ON);
 		}
 	}
 }
@@ -69,26 +69,26 @@ static void dancing_light()
 	switch(step)
 	{
 		case 0:
-			digitalWrite(C_LED_PIN, LOW);
-			digitalWrite(A_LED_PIN, HIGH);
+			digitalWrite(C_LED_PIN, LED_OFF);
+			digitalWrite(A_LED_PIN, LED_ON);
 			break;
 
 		case 1:
-			digitalWrite(A_LED_PIN, LOW);
-			digitalWrite(B_LED_PIN, HIGH);
+			digitalWrite(A_LED_PIN, LED_OFF);
+			digitalWrite(B_LED_PIN, LED_ON);
 			break;
 
 		case 2:
-			digitalWrite(B_LED_PIN, LOW);
-			digitalWrite(C_LED_PIN, HIGH);
+			digitalWrite(B_LED_PIN, LED_OFF);
+			digitalWrite(C_LED_PIN, LED_ON);
 			break;
 	}
 }
 static void clear_leds()
 {
-	digitalWrite(A_LED_PIN, LOW);
-	digitalWrite(B_LED_PIN, LOW);
-	digitalWrite(C_LED_PIN, LOW);
+	digitalWrite(A_LED_PIN, LED_OFF);
+	digitalWrite(B_LED_PIN, LED_OFF);
+	digitalWrite(C_LED_PIN, LED_OFF);
 	motor_light = false;
 	led_mode = NORMAL_LEDS;
 }
diff --git a/ArduCopter/system.pde b/ArduCopter/system.pde
index be4bc71d49..7e543053be 100644
--- a/ArduCopter/system.pde
+++ b/ArduCopter/system.pde
@@ -92,10 +92,18 @@ static void init_ardupilot()
 	report_version();
 
 	// setup IO pins
-	pinMode(C_LED_PIN, OUTPUT);				// GPS status LED
 	pinMode(A_LED_PIN, OUTPUT);				// GPS status LED
-	pinMode(B_LED_PIN, OUTPUT);				// GPS status LED
-	pinMode(SLIDE_SWITCH_PIN, INPUT);		// To enter interactive mode
+  digitalWrite(A_LED_PIN, LED_OFF);
+
+  pinMode(B_LED_PIN, OUTPUT);				// GPS status LED
+  digitalWrite(B_LED_PIN, LED_OFF);
+
+  pinMode(C_LED_PIN, OUTPUT);				// GPS status LED
+  digitalWrite(C_LED_PIN, LED_OFF);
+
+#if SLIDE_SWITCH_PIN > 0
+  pinMode(SLIDE_SWITCH_PIN, INPUT);		// To enter interactive mode
+#endif
 	pinMode(PUSHBUTTON_PIN, INPUT);			// unused
 	DDRL |= B00000100;						// Set Port L, pin 2 to output for the relay
 
@@ -141,13 +149,13 @@ static void init_ardupilot()
 		while (true) {
 			delay(1000);
 			if(motor_light){
-				digitalWrite(A_LED_PIN, HIGH);
-				digitalWrite(B_LED_PIN, HIGH);
-				digitalWrite(C_LED_PIN, HIGH);
+				digitalWrite(A_LED_PIN, LED_ON);
+				digitalWrite(B_LED_PIN, LED_ON);
+				digitalWrite(C_LED_PIN, LED_ON);
 			}else{
-				digitalWrite(A_LED_PIN, LOW);
-				digitalWrite(B_LED_PIN, LOW);
-				digitalWrite(C_LED_PIN, LOW);
+				digitalWrite(A_LED_PIN, LED_OFF);
+				digitalWrite(B_LED_PIN, LED_OFF);
+				digitalWrite(C_LED_PIN, LED_OFF);
 			}
 			motor_light = !motor_light;
 		}
@@ -236,7 +244,7 @@ static void init_ardupilot()
 	// menu; they must reset in order to fly.
 	//
 	if (check_startup_for_CLI()) {
-		digitalWrite(A_LED_PIN,HIGH);		// turn on setup-mode LED
+		digitalWrite(A_LED_PIN, LED_ON);		// turn on setup-mode LED
 		Serial.printf_P(PSTR("\nCLI:\n\n"));
         run_cli();
 	}
diff --git a/ArduCopter/test.pde b/ArduCopter/test.pde
index e83a72a8ee..45455536f1 100644
--- a/ArduCopter/test.pde
+++ b/ArduCopter/test.pde
@@ -763,14 +763,14 @@ test_wp(uint8_t argc, const Menu::arg *argv)
    delay(1000);
     while(1){
            if (Serial3.available()){
-                   digitalWrite(B_LED_PIN, HIGH); // Blink Yellow LED if we are sending data to GPS
+                   digitalWrite(B_LED_PIN, LED_ON); // Blink Yellow LED if we are sending data to GPS
                    Serial1.write(Serial3.read());
-                   digitalWrite(B_LED_PIN, LOW);
+                   digitalWrite(B_LED_PIN, LED_OFF);
            }
            if (Serial1.available()){
-                   digitalWrite(C_LED_PIN, HIGH); // Blink Red LED if we are receiving data from GPS
+                   digitalWrite(C_LED_PIN, LED_ON); // Blink Red LED if we are receiving data from GPS
                    Serial3.write(Serial1.read());
-                   digitalWrite(C_LED_PIN, LOW);
+                   digitalWrite(C_LED_PIN, LED_OFF);
            }
            if(Serial.available() > 0){
                    return (0);