the led work light on my hp impact driver stays on all the time, even with the battery out.

Diagnosis

The Ryobi ONE+ HP Brushless Impact Driver (PBIW01B) utilizes a sophisticated brushless controller that incorporates several high-capacity capacitors to smooth out voltage spikes and ensure the brushless motor receives a steady stream of current. When the LED work light remains illuminated even after the 18V battery pack has been physically removed, it is almost always due to residual electrical energy stored within these capacitors on the main PCB (Printed Circuit Board). Essentially, the capacitors act as temporary batteries. If the tool was used under heavy load or the trigger was released abruptly, a significant amount of charge can remain trapped in the circuit. Because the LED requires a very low current to operate, this residual energy is sufficient to keep the diode lit for several minutes—or in some cases, hours—until the energy naturally bleeds off through the circuit's internal resistance. You can confirm this is a capacitor issue if the light slowly dims over a period of 10 to 30 minutes without any intervention.

How to Fix It

To clear the stored energy and reset the LED state, you must manually drain the capacitors. Follow these exact steps:

1. Remove the 18V ONE+ battery pack completely from the tool base. Ensure there is no physical contact between the battery terminals and the tool's intake pins.
2. While the battery is removed, firmly depress and hold the variable speed trigger. Hold it in the fully engaged position for a minimum of 15 to 20 seconds. This forces the stored energy to attempt to power the brushless motor, which quickly exhausts the capacitor's reserves.
3. Release the trigger and observe the LED work light. It should now be completely dark.
4. Inspect the trigger for any physical sticking or debris; if the trigger is partially depressed due to a worn spring, the circuit may remain "closed," causing the light to draw power more aggressively.
5. Slide the battery pack back into the housing until it clicks securely.
6. Test the tool by pulling the trigger briefly to ensure the light activates and deactivates in synchronization with your trigger pull.

If That Didn't Work

• Check for Trigger Switch Failure: If the light stays on even after draining the capacitors and the tool begins spinning the moment the battery is inserted, the trigger switch assembly has likely suffered an internal mechanical failure or a short circuit. This requires the replacement of the trigger switch module.
• Inspect for Moisture Intrusion: If the tool was used in damp conditions, moisture or conductive metallic dust can create a "bridge" across the PCB traces, bypassing the switch. Use a canister of compressed air to blow out the vents around the trigger and motor housing, then let the tool dry in a low-humidity environment for 24 hours.
• Verify Battery Terminal Integrity: Inspect the battery terminals for any bent pins or carbon buildup (black soot). A bridged terminal can sometimes cause erratic behavior in the control board's logic, though this is less common for a "no battery" light issue. Clean terminals with a cotton swab and 90% isopropyl alcohol.
• Control Board Replacement: If the LED remains lit indefinitely without a battery and the trigger drain method fails, the MOSFETs or the capacitor itself on the brushless controller board may have failed in a "closed" state. This is a hardware failure that requires replacing the entire internal electronics assembly.

Heads Up

• Avoid using conductive lubricants (like graphite) near the trigger assembly, as these can migrate into the brushless controller and cause electrical shorts that mimic this LED issue.
• When storing the tool for long periods, remove the battery. This prevents deep discharge of the cells and reduces the likelihood of capacitor leakage on the PCB.
• Be aware that the HP Brushless series generates significantly more heat than the standard brushed models; avoid letting the tool overheat to the point where the plastic housing softens, as this can warp the trigger alignment and cause the light to stay on.
• Never attempt to probe the PCB with a multimeter while the battery is inserted unless you are trained in electronics, as the high-current rails on the PBIW01B can easily blow a fuse in your meter or damage the board.