How do I troubleshoot a 60" light bar that only works with the key on but not when the truck is running?Updated a month ago

If your 60" light bar powers on with the key in the “on” position but shuts off once the truck is running, it usually points to a wiring or power source issue. Here are steps to check:

• Confirm that the light bar is wired to a proper 12V power source that remains active while the vehicle is running.

• Inspect the connection point—some ignition or accessory circuits lose voltage once the engine starts. If the light bar is tied into one of these, it will shut off under load.

• Verify the ground connection is secure and making good contact with bare metal. A weak or painted ground can cause intermittent operation.

• Check for cut, pinched, or loose wires that may be interrupting power once vibration from the engine starts.

• Inspect the inline fuse and relay (if used) to make sure they are properly rated and functioning.