Replace The Battery Cables on a Subaru Impreza
The battery cables on my 2005 Subaru WRX STI needed to be replaced. After many years and miles, the wires themselves began to corrode pretty heavily. This reduced the quality of the ground and power getting to all parts of the car.
If you're dealing with electrical gremlins, especially battery charging issues, you should inspect your battery cables and consider replacing them if needed.
Note that the positive terminal does not come with the OEM battery cables. If you wish to replace it, I included it in the parts list.
Disconnect the positive and negative wires from the battery.
Disconnect the terminal to fuse box wire.
Disconnect the fender ground.
Disconnect the ground to the transmission.
Disconnect the power to the starter.
Remove the battery cable harness.
Note, there's a plastic clip that holds it in place below the master cylinder.
Snake the new cable into position.
Connect the starter power wire.
Connect the transmission ground.
Connect the fender ground.
Clip the harness into the retainer near the master cylinder.
Re-connect the fuse box to battery wire.
Reconnect the battery terminals.
I've included Subaru's part diagram for this wire harness below