A faulty switch on your Makita angle grinder creates serious safety concerns and prevents productive work. Whether your grinder won't start, runs intermittently or won't shut off, the trigger switch is often the culprit. Replacing a failed switch is straightforward with basic tools and the correct replacement part. Here's your complete step-by-step guide.

Signs You Need a New Switch

Intermittent Operation: Grinder starts only when you hold the trigger at certain angles or with extra pressure.

No Power: Grinder won't start despite a good power cord and outlet.

Won't Shut Off: Grinder continues running after releasing the trigger.

Burnt Smell or Visible Damage: Scorched plastic or melted components around the trigger indicate electrical failure.

Tools and Parts You'll Need

❑ Replacement switch compatible with your Makita model 

❑ Phillips and flathead screwdrivers 

❑ Needle-nose pliers (for wire connections) 

❑ Multimeter (optional, for testing) 

❑ Clean workspace with good lighting

Step-by-Step Switch Replacement

Step 1: Disconnect Power Unplug the grinder completely. For battery-powered models, remove the battery. Never attempt switch replacement with power connected.

Step 2: Remove the Handle Most Makita angle grinders have side handles secured with screws or clamps. Remove the side handle to access housing screws underneath or behind it.

Step 3: Open the Housing Locate all housing screws, typically 4-6 screws securing the two housing halves. Remove these screws carefully and keep them organized. Gently separate the housing halves.

Step 4: Access the Switch Assembly With housing open, locate the trigger switch assembly near the handle area. Note how wires connect to the switch terminals before disconnecting anything.

Step 5: Disconnect the Old Switch Remove wire connections from the switch terminals. Some switches use spade connectors that slide off, while others require desoldering. Note wire colors and positions for correct reconnection.

Step 6: Remove Mounting Hardware Switches typically mounted with small screws or clips. Remove these fasteners and extract the old switch from the housing.

Step 7: Install the New Switch Position the replacement switch in the housing mount. Secure with original screws or clips, ensuring the switch trigger moves freely without binding.

Step 8: Reconnect Wiring Attach wires to the new switch terminals in the same configuration as the original. Ensure connections are tight and secure.

Step 9: Test Before Closing Before reassembling the housing, plug in the grinder and test switch operation. The grinder should start smoothly when you press the trigger and stop immediately when released.

Step 10: Reassemble Housing Once operation is confirmed, carefully close the housing halves. Replace all screws, ensuring they're snug but not overtightened. Reinstall the side handle.

Safety First

Never bypass safety switches or modify electrical connections. Use only switches designed specifically for your Makita model. Incorrect switches may not handle the electrical load or fit properly, creating fire and shock hazards. Need help knowing what switch to get? Contact our customer support team for help!