On my 1996, I drilled a hole in the firewall directly to the outside of the heater/AC box. it was a pain in the *** to drill the hole for a 1ga. wire but it worked out. Best part is it puts the wire in a straight line to the battery...
The phrase "Go for it, man" is usually followed by carnage and a trail full of broken parts
-1996 XJ, 4.0L, AW4, np242, D30/Chrysler 8.25"
-1989 XJ, 4.0L, AX-15, np231, D30/D35
-1987 K5 Blazer, EFI 468ci BBC, sm465, np205, Dana 60/14 bolt, rear discs, DEEEEEETROITS front and rear, hydro assist, cross-over steering. It's loud, locked and loaded