diff --git a/tests/components/modbus/conftest.py b/tests/components/modbus/conftest.py
index ca3e44dbe1d..ce6e6585512 100644
--- a/tests/components/modbus/conftest.py
+++ b/tests/components/modbus/conftest.py
@@ -64,6 +64,8 @@ async def setup_base_test(
 
     entity_id = f"{entity_domain}.{sensor_name}"
     device = hass.states.get(entity_id)
+    if device is None:
+        pytest.fail("CONFIG failed, see output")
     return entity_id, now, device
 
 
diff --git a/tests/components/modbus/test_modbus_switch.py b/tests/components/modbus/test_modbus_switch.py
index 75255389bea..da2ff953660 100644
--- a/tests/components/modbus/test_modbus_switch.py
+++ b/tests/components/modbus/test_modbus_switch.py
@@ -3,9 +3,22 @@ from datetime import timedelta
 
 import pytest
 
-from homeassistant.components.modbus.const import CALL_TYPE_COIL, CONF_COILS
+from homeassistant.components.modbus.const import (
+    CALL_TYPE_COIL,
+    CALL_TYPE_REGISTER_HOLDING,
+    CONF_COILS,
+    CONF_REGISTER,
+    CONF_REGISTERS,
+)
 from homeassistant.components.switch import DOMAIN as SWITCH_DOMAIN
-from homeassistant.const import CONF_NAME, CONF_SLAVE, STATE_OFF, STATE_ON
+from homeassistant.const import (
+    CONF_COMMAND_OFF,
+    CONF_COMMAND_ON,
+    CONF_NAME,
+    CONF_SLAVE,
+    STATE_OFF,
+    STATE_ON,
+)
 
 from .conftest import run_base_read_test, setup_base_test
 
@@ -61,3 +74,113 @@ async def test_coil_switch(hass, mock_hub, regs, expected):
         expected,
         now + timedelta(seconds=scan_interval + 1),
     )
+
+
+@pytest.mark.parametrize(
+    "regs,expected",
+    [
+        (
+            [0x00],
+            STATE_OFF,
+        ),
+        (
+            [0x80],
+            STATE_OFF,
+        ),
+        (
+            [0xFE],
+            STATE_OFF,
+        ),
+        (
+            [0xFF],
+            STATE_OFF,
+        ),
+        (
+            [0x01],
+            STATE_ON,
+        ),
+    ],
+)
+async def test_register_switch(hass, mock_hub, regs, expected):
+    """Run test for given config."""
+    switch_name = "modbus_test_switch"
+    scan_interval = 5
+    entity_id, now, device = await setup_base_test(
+        switch_name,
+        hass,
+        mock_hub,
+        {
+            CONF_REGISTERS: [
+                {
+                    CONF_NAME: switch_name,
+                    CONF_REGISTER: 1234,
+                    CONF_SLAVE: 1,
+                    CONF_COMMAND_OFF: 0x00,
+                    CONF_COMMAND_ON: 0x01,
+                },
+            ]
+        },
+        SWITCH_DOMAIN,
+        scan_interval,
+    )
+
+    await run_base_read_test(
+        entity_id,
+        hass,
+        mock_hub,
+        CALL_TYPE_REGISTER_HOLDING,
+        regs,
+        expected,
+        now + timedelta(seconds=scan_interval + 1),
+    )
+
+
+@pytest.mark.parametrize(
+    "regs,expected",
+    [
+        (
+            [0x40],
+            STATE_ON,
+        ),
+        (
+            [0x04],
+            STATE_OFF,
+        ),
+        (
+            [0xFF],
+            STATE_OFF,
+        ),
+    ],
+)
+async def test_register_state_switch(hass, mock_hub, regs, expected):
+    """Run test for given config."""
+    switch_name = "modbus_test_switch"
+    scan_interval = 5
+    entity_id, now, device = await setup_base_test(
+        switch_name,
+        hass,
+        mock_hub,
+        {
+            CONF_REGISTERS: [
+                {
+                    CONF_NAME: switch_name,
+                    CONF_REGISTER: 1234,
+                    CONF_SLAVE: 1,
+                    CONF_COMMAND_OFF: 0x04,
+                    CONF_COMMAND_ON: 0x40,
+                },
+            ]
+        },
+        SWITCH_DOMAIN,
+        scan_interval,
+    )
+
+    await run_base_read_test(
+        entity_id,
+        hass,
+        mock_hub,
+        CALL_TYPE_REGISTER_HOLDING,
+        regs,
+        expected,
+        now + timedelta(seconds=scan_interval + 1),
+    )