the rear plug sensor on the diff housing is still there; likely left there to keep the diff fluid from getting dirty or sloshing out.

i don't see the green warning light in the dash. i suspect that the bulb was removed out of annoyance.

the pigtail i have no idea where it is. i hope the previous owner wrapped it up somewhere or maybe it rotted away and he just cut it off and left the plug in the diff.

how easy would it be to rewire the plug so the RABS is operational again?

 

i'm not sure that the bigger trucks had ABS in 1989.
I would say the rearend is out of somethng newer.

 

Pretty unlikely that the truck had ABS from the factory. Look under the hood for the ABS HCU. You probably won't find one.

As noted, it's probably had a rear end swap.

Steve

 

My 89 has Abs on the rear axle.

 

Cant be too hard to just wire it up, if the harness wires are still back there somewhere. You can probably buy the plug from a junkyard, from a dealer, or from Motorcraft. Their website has a great list of connectors. Or country boy it with a couple Radio Shack spades.

I just soldered mine back together tonight after finding apparent racoon damage to the wiring. Left about 10 inches of wire attached to the connector.... and nibble marks on the wire loom cover.

Sucker stood under my oak tree feeding on other stuff while I repaired the wiring. I think I will leave a roll of #14 green out there tonight for him!