dust blower on my gst18v stopped working, just a little puff when i start the saw then nothing.

Diagnosis

The Bosch GST18V-60CN features an integrated dust blower designed to keep the cut line clear. When you experience a "single puff" of air followed by total silence, it indicates that the blower motor is attempting to engage but is meeting immediate resistance or is physically obstructed. This is rarely an electrical failure of the motor itself; instead, it is typically caused by "compacted sawdust plugs." Fine particles from MDF or pressure-treated lumber mix with moisture or resin, creating a hard, cement-like plug inside the narrow plastic air channel. The initial puff occurs because the motor has enough torque to move a small amount of air trapped in the immediate nozzle, but the blockage further back in the internal conduit prevents a continuous flow. In some cases, the internal plastic guide that directs air from the fan to the blade area has shifted or cracked, causing the air to leak internally into the motor housing rather than exiting through the nozzle. You can confirm a blockage by checking the intake vents on the front of the tool; if they are coated in a thick layer of dust, the blower cannot pull in the air required to create a stream.

How to Fix It

To clear the obstruction and restore full airflow, follow these precise steps:

1. Remove the 18V battery pack completely to ensure the tool cannot accidentally trigger during cleaning.
2. Locate the blower outlet nozzle situated just above the blade guard. Use a high-pressure compressed air canister or a shop compressor with a long-reach needle nozzle.
3. Insert the needle nozzle directly into the blower outlet and fire short, powerful bursts of air. This pushes the blockage backward toward the motor.
4. Flip the tool over and locate the primary air intake vents on the front face of the GST18V-60CN housing. Blow compressed air directly into these vents. This "back-flushing" method is critical for dislodging the compacted sawdust plugs that a front-facing blow cannot reach.
5. Use a vacuum cleaner with a narrow crevice tool on the intake vents to suck out the debris you just loosened.
6. Reinsert the battery and perform a test trigger. The blower should now maintain a constant stream of air throughout the duration of the trigger pull.

If That Didn't Work

• Inspect the Blower Nozzle for Cracks: Remove the two T10 Torx screws securing the front plastic guard assembly. Carefully lift the guard to inspect the plastic tube leading to the nozzle. If the tube is cracked or disconnected from the fan housing, the air will blow into the tool's internals instead of at the blade. Use a high-strength epoxy or a plastic weld to seal any cracks.
• Deep Clean the Fan Impeller: If the "puff" is very weak, the fan impeller itself may be coated in grime. With the front housing removed, use a soft brush and isopropyl alcohol to clean the blades of the small blower fan. Even a thin layer of sawdust on the impeller blades reduces the RPM and air volume significantly.
• Check for Foreign Object Obstruction: Occasionally, a small piece of wood chip or a metal shaving can get lodged in the impeller. Rotate the fan manually with a toothpick to ensure it spins freely without any grinding or resistance.
• Verify Trigger Contact: If the blower is an optional setting on your specific regional variant, ensure the selector switch is fully engaged. If the internal contact for the blower circuit is oxidized, use a shot of electronic contact cleaner (like DeoxIT) into the trigger assembly.

Heads Up

• Avoid Wet Dust: Never use the blower when cutting damp or "green" wood, as the moisture causes sawdust to clump and harden inside the blower channel, leading to the exact failure you experienced.
• Weekly Maintenance: Every 10-15 hours of use, use a vacuum on the intake vents to prevent the buildup of a "dust cake" that chokes the motor.
• Blade Compatibility: Ensure you are using genuine Bosch T-shank blades; oversized or non-standard blades can sometimes obstruct the airflow path of the blower nozzle.
• Avoid Over-Pressurizing: When using a compressor to clear the lines, keep the pressure below 90 PSI to avoid cracking the internal plastic air conduits.