Blower Motor

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Project Box
Part Number(s):
Part Cost: $30 to $450
Best Place to buy: Ebay
Cost to Have it done in a shop: $700+
Difficulty Level: 3
How long it may take: 1 hour
Frequency: Brushes last for about a decade or two of service
Tools needed: 8 mm & 7mm wrench; prying tools (punch, vice, etc) for motor
Special tools needed: Replacement brushes (sold by mercedesource)

Symptoms

The most typical problem with the blower motor is a failure in the brushes of the motor, symptoms include:

  1. Blower will not activate
  2. Blower will turn on and off
  3. Whining noise is made intermittently
  4. Hitting the Blower or hitting a bump in the road may turn it back on

The variance in the part cost is based on the nature of the problem. Often, just $30 on new brushes is sufficient to fix the problem. Otherwise, used blowers sell for between $40 and $100, while new motors can cost up to $450.

Blower Removal

Blower enclosure installed
  1. Remove underdash panel on passenger side (3 screws under 3 tabs + 2 plastic screws on each side)
  2. Remove three 8mm screws on blower housing plus 1 screw holding the motor to the housing
  3. Unplug blower and remove blower from car
  4. Clean well (lots of dirt from decades of service)
Top view of the Blower motor

Brush Replacement

The motor must be opened.

  1. Remove tab that holds plug covers
  2. Undo plugs and remove blower cage from blower base using a 7 or 6mm screw
  3. Undo the tabs that hold the springs for the brushes, be careful of springs that will shoot out (1 on each brush)
  4. Solder brush wires until they're disconnected, match length to new wire on new brushes
  5. Solder new wires in along with brushes, taking note of brush orientation on grooves
  6. Reinstall spring into brackets and gently tap the tabs that hold the spring back into place to hold the springs
  7. Reinstall blower motor + blower cage unto base
  8. Reinstall entire blower assembly (cage + motor + base) into car