diff --git a/homeassistant/components/binary_sensor/modbus.py b/homeassistant/components/binary_sensor/modbus.py
index fb6f84c318d..00dc588a468 100644
--- a/homeassistant/components/binary_sensor/modbus.py
+++ b/homeassistant/components/binary_sensor/modbus.py
@@ -49,6 +49,7 @@ class ModbusCoilSensor(BinarySensorDevice):
         self._coil = int(coil)
         self._value = None
 
+    @property
     def name(self):
         """Return the name of the sensor."""
         return self._name
@@ -61,4 +62,10 @@ class ModbusCoilSensor(BinarySensorDevice):
     def update(self):
         """Update the state of the sensor."""
         result = modbus.HUB.read_coils(self._slave, self._coil, 1)
-        self._value = result.bits[0]
+        try:
+            self._value = result.bits[0]
+        except AttributeError:
+            _LOGGER.error(
+                'No response from modbus slave %s coil %s',
+                self._slave,
+                self._coil)
diff --git a/homeassistant/components/modbus.py b/homeassistant/components/modbus.py
index aa958715a48..9075eab2cdd 100644
--- a/homeassistant/components/modbus.py
+++ b/homeassistant/components/modbus.py
@@ -6,13 +6,15 @@ https://home-assistant.io/components/modbus/
 """
 import logging
 import threading
+import os
 
 import voluptuous as vol
 
 import homeassistant.helpers.config_validation as cv
+from homeassistant.config import load_yaml_config_file
 from homeassistant.const import (
     EVENT_HOMEASSISTANT_START, EVENT_HOMEASSISTANT_STOP,
-    CONF_HOST, CONF_METHOD, CONF_PORT)
+    CONF_HOST, CONF_METHOD, CONF_PORT, ATTR_STATE)
 
 DOMAIN = 'modbus'
 
@@ -50,6 +52,7 @@ CONFIG_SCHEMA = vol.Schema({
 _LOGGER = logging.getLogger(__name__)
 
 SERVICE_WRITE_REGISTER = 'write_register'
+SERVICE_WRITE_COIL = 'write_coil'
 
 ATTR_ADDRESS = 'address'
 ATTR_UNIT = 'unit'
@@ -61,6 +64,11 @@ SERVICE_WRITE_REGISTER_SCHEMA = vol.Schema({
     vol.Required(ATTR_VALUE): vol.All(cv.ensure_list, [cv.positive_int])
 })
 
+SERVICE_WRITE_COIL_SCHEMA = vol.Schema({
+    vol.Required(ATTR_UNIT): cv.positive_int,
+    vol.Required(ATTR_ADDRESS): cv.positive_int,
+    vol.Required(ATTR_STATE): cv.boolean
+})
 
 HUB = None
 
@@ -105,9 +113,18 @@ def setup(hass, config):
         HUB.connect()
         hass.bus.listen_once(EVENT_HOMEASSISTANT_STOP, stop_modbus)
 
+        descriptions = load_yaml_config_file(os.path.join(
+            os.path.dirname(__file__), 'services.yaml')).get(DOMAIN)
+
         # Register services for modbus
-        hass.services.register(DOMAIN, SERVICE_WRITE_REGISTER, write_register,
-                               schema=SERVICE_WRITE_REGISTER_SCHEMA)
+        hass.services.register(
+            DOMAIN, SERVICE_WRITE_REGISTER, write_register,
+            descriptions.get(SERVICE_WRITE_REGISTER),
+            schema=SERVICE_WRITE_REGISTER_SCHEMA)
+        hass.services.register(
+            DOMAIN, SERVICE_WRITE_COIL, write_coil,
+            descriptions.get(SERVICE_WRITE_COIL),
+            schema=SERVICE_WRITE_COIL_SCHEMA)
 
     def write_register(service):
         """Write modbus registers."""
@@ -125,6 +142,13 @@ def setup(hass, config):
                 address,
                 int(float(value)))
 
+    def write_coil(service):
+        """Write modbus coil."""
+        unit = service.data.get(ATTR_UNIT)
+        address = service.data.get(ATTR_ADDRESS)
+        state = service.data.get(ATTR_STATE)
+        HUB.write_coil(unit, address, state)
+
     hass.bus.listen_once(EVENT_HOMEASSISTANT_START, start_modbus)
 
     return True
diff --git a/homeassistant/components/sensor/modbus.py b/homeassistant/components/sensor/modbus.py
index d8a5be9ab49..9453daea413 100644
--- a/homeassistant/components/sensor/modbus.py
+++ b/homeassistant/components/sensor/modbus.py
@@ -117,17 +117,20 @@ class ModbusRegisterSensor(Entity):
                 self._register,
                 self._count)
         val = 0
-        if not result:
+
+        try:
+            registers = result.registers
+        except AttributeError:
             _LOGGER.error("No response from modbus slave %s register %s",
                           self._slave, self._register)
             return
         if self._data_type == DATA_TYPE_FLOAT:
             byte_string = b''.join(
-                [x.to_bytes(2, byteorder='big') for x in result.registers]
+                [x.to_bytes(2, byteorder='big') for x in registers]
             )
             val = struct.unpack(">f", byte_string)[0]
         elif self._data_type == DATA_TYPE_INT:
-            for i, res in enumerate(result.registers):
+            for i, res in enumerate(registers):
                 val += res * (2**(i*16))
         self._value = format(
             self._scale * val + self._offset, '.{}f'.format(self._precision))
diff --git a/homeassistant/components/services.yaml b/homeassistant/components/services.yaml
index db71b2322fa..97e947fff06 100644
--- a/homeassistant/components/services.yaml
+++ b/homeassistant/components/services.yaml
@@ -483,3 +483,28 @@ apple_tv:
   apple_tv_scan:
     description: Scan for Apple TV devices.
 
+modbus:
+  write_register:
+    description: Write to a modbus holding register
+    fields:
+      unit:
+        description: Address of the modbus unit
+        example: 21
+      address:
+        description: Address of the holding register to write to
+        example: 0
+      value:
+        description: Value to write
+        example: 0
+  write_coil:
+    description: Write to a modbus coil
+    fields:
+      unit:
+        description: Address of the modbus unit
+        example: 21
+      address:
+        description: Address of the register to read
+        example: 0
+      state:
+        description: State to write
+        example: false
diff --git a/homeassistant/components/switch/modbus.py b/homeassistant/components/switch/modbus.py
index 95168d5b830..e6342617f28 100644
--- a/homeassistant/components/switch/modbus.py
+++ b/homeassistant/components/switch/modbus.py
@@ -70,10 +70,10 @@ class ModbusCoilSwitch(ToggleEntity):
     def update(self):
         """Update the state of the switch."""
         result = modbus.HUB.read_coils(self._slave, self._coil, 1)
-        if not result:
+        try:
+            self._is_on = bool(result.bits[0])
+        except AttributeError:
             _LOGGER.error(
                 'No response from modbus slave %s coil %s',
                 self._slave,
                 self._coil)
-            return
-        self._is_on = bool(result.bits[0])