the forward/reverse slider switch is stuck and won't move on my ps31.

Diagnosis

The forward/reverse slider switch on the Bosch PS31-2A typically jams due to the accumulation of fine particulate matter—specifically gypsum dust from drywall or silica dust from concrete—which migrates past the housing seams and settles into the sliding track. Because the PS31-2A uses a plastic-on-plastic sliding interface with a small tension spring, these particles act like sandpaper or a wedge, creating enough friction to lock the slider in place. In some cases, the jam is caused by "plastic creep" or a slight misalignment of the internal switch actuator. If the tool was dropped while the switch was in a transitional state, the internal detent (the mechanism that "clicks" the switch into place) can jump its track, physically blocking the slider from moving forward or backward. You can confirm this by attempting to gently wiggle the switch; if it moves a fraction of a millimeter but won't slide, it is likely debris. If it feels completely rigid as if welded, it is likely a mechanical failure of the internal spring or a broken plastic tab.

How to Fix It

To resolve a jammed slider without fully dismantling the tool, follow this chemical agitation process:

1. Remove the 12V Max battery pack entirely to prevent any accidental motor engagement or short-circuiting during the cleaning process.
2. Use a can of non-conductive, fast-evaporating electrical contact cleaner (such as CRC QD Contact Cleaner). Do not use WD-40 or penetrating oils, as these attract more dust and can degrade the plastic housing over time.
3. Insert the straw nozzle of the cleaner directly into the gaps surrounding the slider switch. Spray liberally for 3-5 seconds, ensuring the liquid penetrates deep into the switch housing.
4. Wait 60 seconds for the solvent to break down the dried contaminants.
5. While the area is still wet, use your thumb to apply firm, rhythmic pressure to the switch, attempting to move it in small increments. Do not force it with a tool; use manual pressure to "walk" the switch from the center (neutral) position toward the forward setting.
6. Once the switch moves slightly, spray the cleaner again and vigorously slide the switch back and forth across all three positions (Forward, Reverse, and Center Lock) for 30 seconds.
7. Use a can of compressed air to blow out the remaining loosened debris from the switch cavity.
8. Allow the tool to air-dry for 5 minutes before reinserting the battery and testing the function.

If That Didn't Work

• Internal Switch Replacement: If the switch remains immobile, the internal spring or the plastic actuator (Part No. 2 607 001 039) has likely snapped. You will need to remove the outer housing screws, carefully separate the clamshell, and replace the switch assembly. Ensure the spring is seated correctly in the groove before closing the housing, or the switch will not lock in the center position.
• Housing Alignment Check: Check for any cracks in the plastic casing around the switch area. If the tool was dropped, the housing may have compressed, pinching the slider. You can sometimes resolve this by slightly loosening the housing screws, aligning the casing, and retightening them.
• Manual Detent Reset: If the switch is stuck due to a jumped detent, you can sometimes "shock" it back into place. With the battery removed, give the side of the tool (near the switch) a few sharp taps with a rubber mallet. This vibration can occasionally reseat a displaced internal spring.
• Deep Clean Disassembly: If the tool has been used in extremely dusty environments, a surface spray won't work. You must open the case and use a soft-bristle brush and isopropyl alcohol to manually scrub the sliding rails of the switch mechanism.

Heads Up

• Never use pliers or screwdrivers to pry the slider switch; the plastic tabs on the PS31-2A are brittle and will snap, rendering the tool permanently stuck in one direction.
• Always ensure the slider is in the center "Lock" position before performing any maintenance or changing accessories to prevent the tool from spinning up unexpectedly.
• Avoid using silicone-based lubricants on the switch; while they reduce friction, they create a sticky film that traps dust, leading to a more severe jam in the future.
• Periodically blow out the switch area with compressed air after every project involving masonry or drywall to prevent particulate buildup.