Replacing the brushes on the Saab 9000 heater blower motor

Introduction

After many years of operation, the blower motor on the Saab 9000 will become erratic and eventually cease to function altogether. In every case I have seen, this is due to the motor brushes being worn down almost to nothing, despite little apparent wear to the commutator. For a long time this meant replacement of the blower motor, which is very expensive even as an aftermarket replacement. However, suitable replacement brushes are now available at low cost and replacement is a DIY proposition, as documented here.

Time required

Around 20 minutes, once the motor has been removed from the car

Tools required

• Small, long-nose pliers
• Soldering iron

Procedure

1. There are two brushes on the motor, each contained within a copper brush holder. The brush has a braided copper lead which is soldered into the ferrule.
   
   
   
   
2. Using a small screwdriver or long-nose pliers, gently bend the end-tabs of the brush-holder outwards. These retain the spring so be careful not to lose it. It won't be under a great deal of tension at this point if the brushes are very worn.
   
   Note in this photograph the brush had worn away almost completely, having parted from the braided lead.
   
   
   
   
3. I retrieved the two springs and a small remnant of one brush.
   
   
   
   
4. The other brush remained attached to its lead.
   
   
   
   
5. In production, the ferrule has been crushed to secure the lead before soldering. Using a soldering iron, heat the ferrule until the solder melts. Once hot, squash the ferrule with a pair of pliers to make it approximately circular again, heat it again to re-melt the solder and pull out the lead. 
   
   
6. The new brushes.
   
   
   
7. Insert the new brush lead into the ferrule from underneath and heat the ferrule to re-melt the solder, pushing the end of the lead up into place.
   
   
8. Insert the brush into the brush-holder, oriented so that the the lead exits from the bottom of the brush.
   
   
9. Insert the spring and hold it compressed while bending the tabs back into place to retain it.
   
   
10. Repeat for the other brush.
    
    
11. Connect to a 12V supply to test the motor, or connect it temporarily to the car. Once satisfied that it is working correctly, refit the motor to the car.