diff --git a/libraries/AP_Relay/AP_Relay.cpp b/libraries/AP_Relay/AP_Relay.cpp
index 75fe1e175cf7f68826085c898483ef2becff55f9..7fb362a4d357b4352ded9483df42a4669466cf25 100644
--- a/libraries/AP_Relay/AP_Relay.cpp
+++ b/libraries/AP_Relay/AP_Relay.cpp
@@ -42,19 +42,23 @@ const AP_Param::GroupInfo AP_Relay::var_info[] PROGMEM = {
     // @Values: -1:Disabled,13:APM2 A9 pin,47:APM1 relay,50:Pixhawk FMU AUX1,51:Pixhawk FMU AUX2,52:Pixhawk FMU AUX3,53:Pixhawk FMU AUX4,54:Pixhawk FMU AUX5,55:Pixhawk FMU AUX6,111:PX4 FMU Relay1,112:PX4 FMU Relay2,113:PX4IO Relay1,114:PX4IO Relay2,115:PX4IO ACC1,116:PX4IO ACC2
     AP_GROUPINFO("PIN2",  1, AP_Relay, _pin[1], -1),
 
+#if AP_RELAY_NUM_RELAYS > 2
     // @Param: PIN3
     // @DisplayName: Third Relay Pin
     // @Description: Digital pin number for 3rd relay control.
     // @User: Standard
     // @Values: -1:Disabled,13:APM2 A9 pin,47:APM1 relay,50:Pixhawk FMU AUX1,51:Pixhawk FMU AUX2,52:Pixhawk FMU AUX3,53:Pixhawk FMU AUX4,54:Pixhawk FMU AUX5,55:Pixhawk FMU AUX6,111:PX4 FMU Relay1,112:PX4 FMU Relay2,113:PX4IO Relay1,114:PX4IO Relay2,115:PX4IO ACC1,116:PX4IO ACC2
     AP_GROUPINFO("PIN3",  2, AP_Relay, _pin[2], -1),
+#endif
 
+#if AP_RELAY_NUM_RELAYS > 3
     // @Param: PIN4
     // @DisplayName: Fourth Relay Pin
     // @Description: Digital pin number for 4th relay control.
     // @User: Standard
     // @Values: -1:Disabled,13:APM2 A9 pin,47:APM1 relay,50:Pixhawk FMU AUX1,51:Pixhawk FMU AUX2,52:Pixhawk FMU AUX3,53:Pixhawk FMU AUX4,54:Pixhawk FMU AUX5,55:Pixhawk FMU AUX6,111:PX4 FMU Relay1,112:PX4 FMU Relay2,113:PX4IO Relay1,114:PX4IO Relay2,115:PX4IO ACC1,116:PX4IO ACC2
     AP_GROUPINFO("PIN4",  3, AP_Relay, _pin[3], -1),
+#endif
 
     AP_GROUPEND
 };
diff --git a/libraries/AP_Relay/AP_Relay.h b/libraries/AP_Relay/AP_Relay.h
index 2aa9a441c5fbf9c58f39b9f3c98d15b016fe7706..fc7b3c6eac9bcf0d59abe7946e0865d88f043e8c 100644
--- a/libraries/AP_Relay/AP_Relay.h
+++ b/libraries/AP_Relay/AP_Relay.h
@@ -15,7 +15,7 @@
 
 #include <AP_Param.h>
 
-#define AP_RELAY_NUM_RELAYS 4
+#define AP_RELAY_NUM_RELAYS 2
 
 /// @class	AP_Relay
 /// @brief	Class to manage the APM relay