The best method is to examine the firewall to locate an existing hole that the factory wiring is routed through.

* If the grommet is large enough, you can share this opening with your amp power wire.


* Most vehicles have plugs that cover existing unused holes in the firewall. You can drill through the plug to create a grommet to accept the amp power wire.


* An alternate method, if an existing hole cannot be found, is to drill a hole in the firewall.
Check both the passenger and engine compartment sides to be certain that no fluid lines or factory cables will be drilled into! Install a grommet to protect the wire from being cut by the metal edge of the drilled hole.