The ground circuit for your Honda Civic brake lights can be found on the rear frame rail. The ground circuit will be on the drivers side frame rail.
the frame!!!
Bolt it to the frame.
It's attached to the ground.
It's attached to the ground.
There are 3 different grounds. Engine to body ground. Engine to frame ground. Engine to battery ground.
The frame is the best ground source on nearly all vehicles (assuming it uses a negative ground system, which is the most common type-negative post of battery is attached to the frame). If the frame can't be used, a metal part attached to the frame *may* be substituted, but always make sure to clean the attachment point to BARE metal, as paint or powder coating can act as an insulator, preventing a good ground connection.
The ground
An A-Frame
From the battery to frame directly under the battery box. From the frame to the engine at the motor mounts with a short ground cable. Usually on the drivers side.
Ground it to the vehicle frame or engine.
you can ground it right to the frame. just find a bare spot and put a screw with the ground wire