If the computer doent turn on when u plug it in to check, you have a bad fuse, somewhere in the compartment in the cab. Mine is passenger side undr the glovebox. I had similar problem with my ranger. Replace that 10 or 20 amp fuse and u will then be able to diagnose ur ABS problem.

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2004 4.0 4x4 5spd xlt with 175k 4.10 axles, extended cab, cranked t-bars (not maxed), painted black interior, 32x11.5x15 bfg a/t and procomp steel rims
60/40 mod with a shorty console