Greetings fellow Micranauts, I'll try to keep it short: I need to pass a wire for a relay from the interior to the engine bay since I'm installing a button horn. Simple task right? Well after hours of inspecting the firewall it looks like it'd be easier to get a camel to go through the eye of a needle. You may see a bundle of wires above the dusty tube shown in this image, that's the only grommet I have found from the engibe bay but even if I passed a wire through there somehow I don't know where it leads to the inside. The other leads are all inside inaccesible plastic tubes.
I have heard that drilling a hole through the firewall is the simplest option, but I'm not 100% sure where the best spot to drill would be, or if any spot will do. Can anyone with more knowledge than me be able to help this beginner DIYer?