diff --git a/Cargo.toml b/Cargo.toml
index 5e5b1fe7..d9e4e02e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,7 +3,7 @@ authors = ["Ryan Summers <ryan.summers@vertigo-designs.com>"]
 edition = "2018"
 readme = "README.md"
 name = "booster"
-version = "0.3.0-rc.1"
+version = "0.3.0-rc.3"
 build = "build.rs"
 resolver = "2"
 
diff --git a/src/hardware/chassis_fans.rs b/src/hardware/chassis_fans.rs
index 3b716d54..504231e5 100644
--- a/src/hardware/chassis_fans.rs
+++ b/src/hardware/chassis_fans.rs
@@ -4,7 +4,8 @@
 //! Copyright (C) 2020 QUARTIQ GmbH - All Rights Reserved
 //! Unauthorized usage, editing, or copying is strictly prohibited.
 //! Proprietary and confidential.
-use super::{I2cError, I2cProxy};
+use super::{I2cError, I2cProxy, MainboardLeds};
+use embedded_hal::digital::v2::OutputPin;
 use max6639::Max6639;
 
 /// The default fan speed on power-up.
@@ -14,6 +15,7 @@ pub const DEFAULT_FAN_SPEED: f32 = 0.2;
 pub struct ChassisFans {
     fans: [Max6639<I2cProxy>; 3],
     duty_cycle: f32,
+    leds: MainboardLeds,
 }
 
 impl ChassisFans {
@@ -25,10 +27,11 @@ impl ChassisFans {
     ///
     /// # Returns
     /// A new fan controller.
-    pub fn new(fans: [Max6639<I2cProxy>; 3]) -> Self {
+    pub fn new(fans: [Max6639<I2cProxy>; 3], leds: MainboardLeds) -> Self {
         ChassisFans {
             fans,
             duty_cycle: DEFAULT_FAN_SPEED,
+            leds,
         }
     }
 
@@ -58,14 +61,24 @@ impl ChassisFans {
         // Bound the duty cycle to a normalized range.
         let duty_cycle = duty_cycle.clamp(0.0, 1.0);
 
+        let leds = &mut self.leds;
+
         // Keep retrying until the configuration succeeds or the maximum number of retry
         // attempts is exhausted.
-        let retry_set = |fan: &mut Max6639<I2cProxy>, subfan, duty_cycle| {
+        let mut retry_set = |fan: &mut Max6639<I2cProxy>, subfan, duty_cycle| {
             for _ in 0..2 {
                 match fan.set_duty_cycle(subfan, duty_cycle) {
-                    Err(max6639::Error::Interface(I2cError::NACK)) => {}
+                    Err(max6639::Error::Interface(I2cError::NACK)) => {
+                        leds.0.set_high().unwrap();
+                        leds.1.set_high().unwrap();
+                        leds.2.set_high().unwrap();
+                    }
                     Err(e) => Err(e).unwrap(),
-                    Ok(_) => break,
+                    Ok(_) => {
+                        leds.0.set_low().unwrap();
+                        leds.1.set_low().unwrap();
+                        leds.2.set_low().unwrap();
+                    }
                 }
             }
         };
diff --git a/src/hardware/mod.rs b/src/hardware/mod.rs
index ae3437bb..488572dd 100644
--- a/src/hardware/mod.rs
+++ b/src/hardware/mod.rs
@@ -50,6 +50,11 @@ pub type Spi = hal::spi::Spi<
     ),
 >;
 
+pub type Led1 = hal::gpio::gpioc::PC8<hal::gpio::Output<hal::gpio::PushPull>>;
+pub type Led2 = hal::gpio::gpioc::PC9<hal::gpio::Output<hal::gpio::PushPull>>;
+pub type Led3 = hal::gpio::gpioc::PC10<hal::gpio::Output<hal::gpio::PushPull>>;
+pub type MainboardLeds = (Led1, Led2, Led3);
+
 #[cfg(feature = "phy_enc424j600")]
 pub type NetworkStack = smoltcp_nal::NetworkStack<
     'static,
diff --git a/src/hardware/setup.rs b/src/hardware/setup.rs
index 848f6bdd..414c2220 100644
--- a/src/hardware/setup.rs
+++ b/src/hardware/setup.rs
@@ -332,6 +332,18 @@ pub fn setup(
     };
 
     let mut fans = {
+        let main_board_leds = {
+            let mut led1 = gpioc.pc8.into_push_pull_output();
+            let mut led2 = gpioc.pc9.into_push_pull_output();
+            let mut led3 = gpioc.pc10.into_push_pull_output();
+
+            led1.set_low().unwrap();
+            led2.set_low().unwrap();
+            led3.set_low().unwrap();
+
+            (led1, led2, led3)
+        };
+
         let fan1 =
             max6639::Max6639::new(i2c_bus_manager.acquire_i2c(), max6639::AddressPin::Pulldown)
                 .unwrap();
@@ -341,7 +353,7 @@ pub fn setup(
             max6639::Max6639::new(i2c_bus_manager.acquire_i2c(), max6639::AddressPin::Pullup)
                 .unwrap();
 
-        ChassisFans::new([fan1, fan2, fan3])
+        ChassisFans::new([fan1, fan2, fan3], main_board_leds)
     };
 
     assert!(fans.self_test(&mut delay));