Hey 99MercMystLS25,
I am in the process of planning out my battery relocation and I cannot find the hole through the firewall that you described. The only "hole through the fuse box mounting bracket" that I could find was an unused bolt hole on the left side but there was no hole in the firewall there. How far up under the dash is this hole? I can see where the wires leave the back of the fuse box and disappear through the firewall but they come out behind the cruise control unit and therefore don't provide any help.
Thanks - Dave
