Heating and Ventilation, Air Recirculation flap actuator, Blender Box (created 2012-07-30 19:26:40 - last update 2016-06-22 20:44:39)
If you are reading this, it's probably because you have a problem with the "Gear-Motor" that moves the air entry flap(s) in your car. These micro-motors control the air recirculation flap / hot & cold air mixing actuator / air distribution flap on cars equipped with Air-conditioning or climate control, to regulate the temperature inside the cabin. These actuators were fitted to French cars from 1985 to 2005 (Peugeot 405, 406, Citroen Saxo, Renault Megane, etc) and to few other European cars (Saab, Land Rover, ...). They have a tendency to break the teeth off the gears, after a few years. These gear-motors are still available for sale at an average price of 300 Eur or $432.00 Aud! So I began milling the gears, using brass, so they never break.

The following tutorial explains how to repair your actuators cheaply, by replacing the damaged gears with remanufactured items in brass. (My contact details are at the end of the tutorial)

  1. Materials needed:
    A Pozidrive head screwdriver #1
    A small hammer
    A drift pin 3mm max or a watchmakers screwdriver 2.9mm max
    A ruler
    A block of wood with a 4mm drilled hole at least 20mm deep
    The failed gear-motor and the two brass gears

  2. Opening the case:
    Remove the 4 screws, carefully remove the cover. 2. If a gear-motor feedback potentiometer is fitted inside the case, be careful not to loose the shaft that passes through servo motor gear (the shaft remains attached to the lid, as per photo below).
    Note: the positioning knob is located underneath as shown in the top left of the following photo. It is only present in some motor reducers (generally only those that are used for the hot & cold air mixing functions).

  3. Tow gears:
    Remove the two biggest gears (they will be replaced).
    Remove (and keep) the O-Ring.

  4. Remove the shaft from smaller gear:
    Place the shaft of the smaller gear in the 4mm hole drilled into the wood and tap it out with a hammer and 3mm drift or a watchmakers screwdriver 2.9mm Max.
    CAUTION: do not scratch the shaft with pliers - it could be easily marked or scored and may then be unusable.

  5. Ready gears for reassembly:
    5. O-Ring and the shaft shown ready for reassembly:

    Push the shaft into the smaller of the two brass gears (it may be necessary to use a hammer to drive the shaft into the gear):

    IMPORTANT: push the shaft so that it is protruding 2 - 2.5mm from the top of the gear (see photo). Use a ruler or calliper to check measurement is correct:

    Note: if the shaft is loose and moves freely through the gear, ignore the above and simply position the shaft in the casing and put the on the shaft, it is automatically centred when the housing is closed.

  6. O-Ring:
    6. Put the O-Ring on the largest gear as shown in the photo below:

  7. Clean the case:
    Before putting the new gears in place, clean the inside of the case in order to remove all the remaining teeth that could still be there (don't forget to clean the cover too).

  8. Small gear:
    Put the small gear in place. The angular position is not important.
    In the case of a loose shaft, first insert the shaft into the housing then place the small gear on the shaft.

  9. Large gear:
    CAUTION: if the feedback potentiometer is present (small gear top left in photo), it is imperative to align the arrows that are engraved on the small top left gear and the large brass gear. Without doing this you may break the unit. To do this, turn the small plastic gear to the position shown in the picture below. Then insert the large brass gear with it's arrow pointing at the plastic gear arrow. Note: the motors that do not have the positioning potentiometer (for example, case control of gear-motors, air recirculating flap), the positioning of the large brass gear is not essential. It is simply that the arrow points to the left in the gear-motor (as pictured below), otherwise it will not be possible to close the case properly.

  10. Lubrication:
    Before closing the case, lubricate the gears meshing areas (contact between Neoprene and metal + metal to metal). Also lubricate the O-Ring and the shafts.

  11. Closing the case:
    The cover should be replaced without too much force, 11. If more than light pressure is required, it could indicate that a shaft and/or the larger gear is misaligned. Remove the cover check and re position as required. If all is well, tighten the 4 cover securing screws.
    It is advisable to test the gear-motor prior to installing. Plug the gear-motor lead in, turn on the ignition then activate the switch, it is normal to hear a little metallic noise during operation.

    In case you have this kind of wheel mounted, make sure the toothed half wheel is fully inserted on the output shaft (see photo) before installing the unit.

Done!! You can contact me by email if you want some gears. My email address is ctrl.alt.sup[AT]free.fr (you have to replace the [AT] by the @ sign of your keyboard).

According to my research, my gears should fit into the following cars:
--- Peugeot 405: ref 644758 = valeo 509221 = C26 838 158J (hot & cold air mixing), ref 6447A5 = valeo 509222 (air recirculation)
--- Peugeot 406: ref 6447A5 = valeo 509222 = F656692K/U =
--- Peugeot 605, Peugeot 406 and Citroen XM: ref 644764 = valeo 509226
--- Peugeot 406 (2 wires version), Citroën Xsara (rare): ref 6447V1 = valeo 509225 = F654294A/U / = C31 654 294 AJ / 16105502201 = C31 654 294 AS / 16105502202
--- Citroen Saxo, Peugeot 106 and Citroen AX: ref 6445G4 = valeo 509219
--- Renault Megane, Renault Scenic, Renault 19, Renault Master, Renault Kangoo II (?): ref 7702163822 = valeo 509229 = F833812R/U =, ref 7701043663
--- Renault 21: ref 7701033462 = valeo 509230, ref 7701034351 = valeo 509231, ref 7701034352 = valeo 509232
--- Renault Master, Renault Trafic, Opel Movano, Vauxhall Movano: ref 7701033462 (?) = valeo 509230 (?)
--- Renault Safrane (air recirculation)
--- Renault Mascott
--- Land Rover Range Rover II: ref STC3259 = valeo 509657
--- Range Rover P38 (système HEVAC)
--- Saab 9-5: ref 5334719, ref 5045711 = 16105502701 = 16105502703, ref 1030209
--- Alpine A610

Non exhaustive list and may contains errors!