I am running wiring for a remote radar detector from grill to interior. I seem to remember from a thread here that you can find a good way under the battery tray? I see a possible path through the box that houses the relays next to the battery but after pulling and tugging a little got nervous with the rats nest of wires and how tight they are.
How have others pulled wire through the firewall? Thanks in advance.
Travis

 

Remove the battery tray. See pic.

 

I thought I remembered under the tray but didn't want to disconnect the battery and lose all my settings if I was wrong.
Thanks