diff --git a/firmware/esp32/xterra-controller/config.h b/firmware/esp32/xterra-controller/config.h
index bf287dd..08a3a35 100644
--- a/firmware/esp32/xterra-controller/config.h
+++ b/firmware/esp32/xterra-controller/config.h
@@ -13,7 +13,8 @@
 #define IGNITION_PIN 34
 
 // UART over CAT5 to Pico dashboard
-#define UART_TX_PIN 21
-#define UART_RX_PIN 22
+#define DASHBOARD_UART_TX_PIN 21
+#define DASHBOARD_UART_RX_PIN 22
+#define DASHBOARD_UART_BAUD   115200
 
-// RS-485/MAX3485 fallback only; not currently planned
+// RS-485/MAX3485 is fallback only and not currently planned.
diff --git a/firmware/esp32/xterra-controller/protocol.h b/firmware/esp32/xterra-controller/protocol.h
index cb86ede..e5fcebc 100644
--- a/firmware/esp32/xterra-controller/protocol.h
+++ b/firmware/esp32/xterra-controller/protocol.h
@@ -4,3 +4,4 @@
 #define MSG_STATUS_RESPONSE      "status_response"
 #define MSG_SET_RELAY            "set_relay"
 #define MSG_RELAY_RESPONSE       "relay_response"
+#define MSG_ERROR                "error"
diff --git a/firmware/esp32/xterra-controller/xterra-controller.ino b/firmware/esp32/xterra-controller/xterra-controller.ino
index 1a602e7..e6bed14 100644
--- a/firmware/esp32/xterra-controller/xterra-controller.ino
+++ b/firmware/esp32/xterra-controller/xterra-controller.ino
@@ -3,10 +3,14 @@
 #include <ArduinoJson.h>
 
 #include "config.h"
+#include "protocol.h"
 #include "relays.h"
 #include "sensors.h"
 
 WebServer server(80);
+HardwareSerial DashboardSerial(2);
+
+String uartLineBuffer;
 
 float batterySOC = 82.0;
 float batteryVoltage = 13.2;
@@ -15,10 +19,8 @@ float batteryRemainingAh = 82.0;
 float batteryRuntimeHours = 12.0;
 float batteryTemp = 76.0;
 
-void handleStatus() {
-
-    DynamicJsonDocument doc(2048);
-
+void buildStatusDocument(JsonDocument& doc) {
+    doc["type"] = MSG_STATUS_RESPONSE;
     doc["timestamp"] = millis();
 
     JsonObject battery = doc.createNestedObject("battery");
@@ -51,41 +53,157 @@ void handleStatus() {
     JsonObject network = doc.createNestedObject("network");
     network["wifi_enabled"] = true;
     network["uart_connected"] = true;
+}
+
+void sendStatus(Stream& output, bool pretty = false) {
+    DynamicJsonDocument doc(2048);
+    buildStatusDocument(doc);
+
+    if (pretty) {
+        serializeJsonPretty(doc, output);
+    } else {
+        serializeJson(doc, output);
+    }
+
+    output.println();
+}
+
+void sendError(Stream& output, const char* message) {
+    DynamicJsonDocument doc(256);
+    doc["type"] = MSG_ERROR;
+    doc["message"] = message;
+    serializeJson(doc, output);
+    output.println();
+}
+
+bool setRelayByName(const char* relayName, bool enabled) {
+    if (strcmp(relayName, "starlink") == 0) {
+        relays.starlink = enabled;
+    } else if (strcmp(relayName, "fridge") == 0) {
+        relays.fridge = enabled;
+    } else {
+        return false;
+    }
+
+    updateRelayOutputs();
+    return true;
+}
+
+void sendRelayResponse(Stream& output, const char* relayName, bool enabled) {
+    DynamicJsonDocument doc(256);
+    doc["type"] = MSG_RELAY_RESPONSE;
+    doc["relay"] = relayName;
+    doc["enabled"] = enabled;
+    doc["ok"] = true;
+    serializeJson(doc, output);
+    output.println();
+}
+
+void handleUartMessage(const String& line) {
+    DynamicJsonDocument doc(512);
+    DeserializationError error = deserializeJson(doc, line);
+
+    if (error) {
+        sendError(DashboardSerial, "invalid_json");
+        return;
+    }
+
+    const char* type = doc["type"] | "";
+
+    if (strcmp(type, MSG_STATUS_REQUEST) == 0) {
+        sendStatus(DashboardSerial);
+        return;
+    }
+
+    if (strcmp(type, MSG_SET_RELAY) == 0) {
+        const char* relayName = doc["relay"] | "";
+        bool enabled = doc["enabled"] | false;
+
+        if (!setRelayByName(relayName, enabled)) {
+            sendError(DashboardSerial, "unknown_relay");
+            return;
+        }
+
+        sendRelayResponse(DashboardSerial, relayName, enabled);
+        return;
+    }
+
+    sendError(DashboardSerial, "unknown_message_type");
+}
+
+void pollDashboardUart() {
+    while (DashboardSerial.available()) {
+        char c = DashboardSerial.read();
+
+        if (c == '\n') {
+            uartLineBuffer.trim();
+
+            if (uartLineBuffer.length() > 0) {
+                handleUartMessage(uartLineBuffer);
+            }
+
+            uartLineBuffer = "";
+        } else if (c != '\r') {
+            uartLineBuffer += c;
+
+            if (uartLineBuffer.length() > 512) {
+                uartLineBuffer = "";
+                sendError(DashboardSerial, "message_too_long");
+            }
+        }
+    }
+}
+
+void handleStatus() {
+    server.setContentLength(CONTENT_LENGTH_UNKNOWN);
+    server.send(200, "application/json", "");
+    sendStatus(server.client(), true);
+}
+
+void handleRelayHttp(const char* relayName, bool enabled) {
+    if (!setRelayByName(relayName, enabled)) {
+        server.send(404, "application/json", "{\"ok\":false,\"error\":\"unknown_relay\"}");
+        return;
+    }
+
+    DynamicJsonDocument doc(256);
+    doc["type"] = MSG_RELAY_RESPONSE;
+    doc["relay"] = relayName;
+    doc["enabled"] = enabled;
+    doc["ok"] = true;
 
     String output;
-    serializeJsonPretty(doc, output);
+    serializeJson(doc, output);
 
     server.send(200, "application/json", output);
 }
 
 void handleStarlinkOn() {
-    relays.starlink = true;
-    updateRelayOutputs();
-    server.send(200, "text/plain", "OK");
+    handleRelayHttp("starlink", true);
 }
 
 void handleStarlinkOff() {
-    relays.starlink = false;
-    updateRelayOutputs();
-    server.send(200, "text/plain", "OK");
+    handleRelayHttp("starlink", false);
 }
 
 void handleFridgeOn() {
-    relays.fridge = true;
-    updateRelayOutputs();
-    server.send(200, "text/plain", "OK");
+    handleRelayHttp("fridge", true);
 }
 
 void handleFridgeOff() {
-    relays.fridge = false;
-    updateRelayOutputs();
-    server.send(200, "text/plain", "OK");
+    handleRelayHttp("fridge", false);
 }
 
 void setup() {
-
     Serial.begin(115200);
 
+    DashboardSerial.begin(
+        DASHBOARD_UART_BAUD,
+        SERIAL_8N1,
+        DASHBOARD_UART_RX_PIN,
+        DASHBOARD_UART_TX_PIN
+    );
+
     Serial.println();
     Serial.println("==================================");
     Serial.println("Xterra Controller Booting");
@@ -117,20 +235,18 @@ void setup() {
     server.begin();
 
     Serial.println("Web Server Started");
+    Serial.println("Dashboard UART Started");
 }
 
 void loop() {
-
     server.handleClient();
+    pollDashboardUart();
 
     static unsigned long lastSensorUpdate = 0;
 
     if (millis() - lastSensorUpdate > 5000) {
-
         updateSensors();
-
         lastSensorUpdate = millis();
-
         Serial.println("Sensor Update");
     }
 }