'89 f250, 5.8, 5 speed, 4x4, rear axle has been replaced, dana 60 full float w/o ABS. I have been told that the wire that plugs into the rear axle is the ABS and vehical speed sensor, if it is the speed sensor, will not beeing pluged in have any efect on mileage, or how the truck runs ?

 

On an 89, it shouldn't cause any problems other than de-activating the RABS. The computer uses a VSS mounted to the speedometer cable drive on the transfercase.

 

thanks, thats what I needed to know.