diff --git a/config/example-extras.cfg b/config/example-extras.cfg
index 5aed46d6..7aea28ee 100644
--- a/config/example-extras.cfg
+++ b/config/example-extras.cfg
@@ -587,6 +587,9 @@
 #pid_integral_max:
 #   The maximum "windup" the integral term may accumulate. The default
 #   is to use the same value as max_power.
+#gcode_id:
+#   If set, the temperature will be reported in M105 queries using the
+#   given id. The default is to not report the temperature via M105.
 
 
 # Additional micro-controllers (one may define any number of sections
diff --git a/klippy/extras/heater_generic.py b/klippy/extras/heater_generic.py
index b08b33f2..fbe13edc 100644
--- a/klippy/extras/heater_generic.py
+++ b/klippy/extras/heater_generic.py
@@ -4,13 +4,5 @@
 #
 # This file may be distributed under the terms of the GNU GPLv3 license.
 
-import logging
-
-class PrinterHeaterGeneric:
-    def __init__(self, config):
-        self.printer = config.get_printer()
-        gcode_id = config.get("gcode_id")
-        self.heater = self.printer.lookup_object('heater').setup_heater(config, gcode_id)
-
 def load_config_prefix(config):
-    return PrinterHeaterGeneric(config)
+    return config.get_printer().lookup_object('heater').setup_heater(config)
diff --git a/klippy/extras/temperature_fan.py b/klippy/extras/temperature_fan.py
index 2bf00303..11fb88c4 100644
--- a/klippy/extras/temperature_fan.py
+++ b/klippy/extras/temperature_fan.py
@@ -21,6 +21,7 @@ class TemperatureFan:
         self.sensor = self.printer.lookup_object('heater').setup_sensor(config)
         self.sensor.setup_minmax(self.min_temp, self.max_temp)
         self.sensor.setup_callback(self.temperature_callback)
+        self.printer.lookup_object('heater').register_sensor(config, self)
         self.speed_delay = self.sensor.get_report_time_delta()
         self.max_speed = config.getfloat('max_speed', 1., above=0., maxval=1.)
         self.min_speed = config.getfloat('min_speed', 0.3, above=0., maxval=1.)
@@ -52,6 +53,8 @@ class TemperatureFan:
     def stats(self, eventtime):
         return False, '%s: temp=%.1f fan_speed=%.3f' % (
             self.name, self.last_temp, self.last_speed_value)
+    def get_temp(self, eventtime):
+        return self.last_temp, self.target_temp
 
 ######################################################################
 # Bang-bang control algo
diff --git a/klippy/heater.py b/klippy/heater.py
index 18a1d67b..5810afae 100644
--- a/klippy/heater.py
+++ b/klippy/heater.py
@@ -248,8 +248,7 @@ class PrinterHeaters:
         sensor = self.setup_sensor(config)
         # Create heater
         self.heaters[heater_name] = heater = Heater(config, sensor)
-        if gcode_id is not None:
-            self.gcode_id_to_sensor[gcode_id] = heater
+        self.register_sensor(config, heater, gcode_id)
         return heater
     def lookup_heater(self, heater_name):
         if heater_name == 'extruder':
@@ -269,6 +268,15 @@ class PrinterHeaters:
         return self.sensor_factories[sensor_type](config)
     def get_gcode_sensors(self):
         return self.gcode_id_to_sensor.items()
+    def register_sensor(self, config, psensor, gcode_id=None):
+        if gcode_id is None:
+            gcode_id = config.get('gcode_id', None)
+            if gcode_id is None:
+                return
+        if gcode_id in self.gcode_id_to_sensor:
+            raise self.printer.config_error(
+                "G-Code sensor id %s already registered" % (gcode_id,))
+        self.gcode_id_to_sensor[gcode_id] = psensor
     def turn_off_all_heaters(self, print_time):
         for heater in self.heaters.values():
             heater.set_temp(print_time, 0.)