Q: Won't start. Replaced starter and relay switch, still won't start. Tested battery and it's good.

Hey there, thank you for asking about your 2001 Nissan Pathfinder. You should check fuse number 18 in the fuse panel under the dash. Test the black and yellow wire at the start interrupt relay to see if it gets power when you turn the key to start. If it does, then you are getting power from the ignition switch. Then check the black and pink wire at the relay to see if you get power when you try and crank the engine. If you get no power, then you may have a bad neutral start switch on the transmission. Try to move your transmission through gears and neutral while trying to crank it, holding the brake in case it starts. If you find it will start in one of the gears, then check the shift linkage. If it’s okay, replace the shift interrupt switch on the transmission. If you want to have this checked by a certified mechanic, a technician from YourMechanic can come to your home or office to inspect your starting problem.