Bosch WTG100 Dryer Won’t Cycle Through Drying Phase

Introduction

When a Bosch WTG100 dryer stops cycling through the drying phase, it can throw a wrench into your laundry routine and cause frustration. The dryer’s cycle consists of multiple stages—drying, venting, cooling, and sometimes a final rinse or fan‑only mode. If the machine stalls after the initial warm‑up but never actually dries the clothes, the problem can stem from anything as simple as a blocked vent to a malfunctioning electronic control board.

This guide walks you through common causes, safety precautions, and step‑by‑step troubleshooting so you can get your Bosch WTG100 back to life. It also covers preventive maintenance and when it’s time to call a professional.

Safety First

Before opening the dryer or inspecting any component, make sure to:

1. Unplug the unit from the mains supply.
2. Wait at least 10 minutes after unplugging before touching the appliance.
3. Clear the area of any flammable materials (cloth, paper, etc.).
4. Use a soft brush or vacuum to clean lint, avoiding contact with hot surfaces.
5. Keep children and pets away while you work.

Failure to follow these steps can lead to electric shock or fire.

Common Causes of a Stuck Drying Phase

If the dryer displays a code, refer to the user manual for a full interpretation.

Step‑by‑Step Troubleshooting

1. Inspect the Lint Filter and Vent Hose

• Remove the lint filter and wipe it with a damp cloth.
• Pull the vent hose from the back of the dryer.
• Vacuum or blow out lint from the hose.
• Check the duct that leads outside for obstructions or kinks.

If you find significant lint, clean thoroughly and repeat the test cycle.

2. Verify Door Operation

• Close the dryer door firmly and listen for the click of the latch.
• Press the “Dry” button; if the door sensor is faulty, the machine will not start.

If the door fails to latch, replace the door switch following the Bosch repair manual.

3. Check the Drive Belt

• Locate the belt at the back of the dryer, near the drum and motor.
• Inspect for cracks, fraying, or breaks.
• If damaged, replace the belt with a model‑specific part.

A new belt will allow the drum to turn smoothly, enabling the dryer to cycle through all stages.

4. Test the Motor

• Listen for any grinding or whirring sounds.
• Touch the motor housing (after unplugging).
• If the motor feels warm or overheated, it may need a new thermal fuse or a new motor.

Motor issues are often flagged by error codes; refer to the user manual for the exact code.

5. Verify Temperature Sensors

• Locate the thermostat (usually near the heating element).
• Check for visible signs of damage or burn marks.
• Use a multimeter to test resistance: at room temperature it should read around 1 kΩ; at higher temperatures it should drop to 0.1 kΩ.

If the reading is outside the expected range, replace the thermostat.

6. Inspect the Control Board

• Open the dryer cabinet by removing the back panel.
• Look for burnt or discolored components.
• Check the power supply: ensure the 120 V line is delivering the proper voltage.

If you see any burnt fuses or blown components, replace them. If the board appears normal, but the dryer still stalls, a deeper electronics issue may be present.

7. Examine the Water Inlet Valve (If Applicable)

Bosch dryers sometimes have a water inlet for steam cycles.

• Check the valve for blockages or leaks.
• Test the valve’s operation using a multimeter to ensure continuity.

A faulty valve can cause moisture buildup that interferes with the drying cycle.

Frequently Asked Questions

Preventive Maintenance Checklist

1. Lint Filter – Clean after every load.
2. Vent Hose – Inspect and clean monthly.
3. Door Seal – Check for tears or wear.
4. Control Panel – Keep dry; avoid spills.
5. Motor – Listen for odd sounds; schedule professional inspection annually.

Adhering to these steps keeps the dryer running efficiently and extends its lifespan.

When to Call a Professional

• The dryer continues to cycle incorrectly after all DIY fixes.
• The control board or motor shows signs of damage.
• The dryer emits unusual noises that you cannot locate.
• You suspect electrical problems beyond basic troubleshooting.

Professional technicians have specialized diagnostic tools and can safely replace high‑voltage components.

Conclusion

A Bosch WTG100 dryer that won’t cycle through the drying phase is usually due to one of a few common issues: blocked vents, faulty sensors, or worn mechanical parts. By following the safety precautions, inspecting key components, and methodically testing each potential failure point, you can often resolve the problem without professional help. Consistent maintenance will reduce the likelihood of future stoppages and keep your laundry routine running smoothly.