You might have a chafed or broken wire in the wiring harness between the differential sensor plug/pigtail & where the wiring harness goes into the cab beneath the driver's seat! I did! 1999 B3000 2WD 91K mi, I cut my sensor pigtail off & checked for continuity. It checked good. Then underneath the driver's seat, there are TWO harness connectors. I checked continuity on the RED wire with a long wire with alligator clips on each end. The red wire checked good. I noticed some CHAFING on some wires directly behind one of the TWO harness connectors under the cab. I continuity checked the green wire (with black stripe) & there was NO CONTINUITY at the harness connector NOR all the way back to the differential pigtail! So... I had a break in the green/black wire somewhere in the harness, where you cannot see, nor get to, as it's between the fuel tank & the frame rail. I ran a new wire all the way back to the sensor pigtail & wire tied (zip tied) it all off. All is GOOD NOW!! P.S. When checking continuity on the TWO wires... also check TO GROUND, in case one of the wires is chafed & ''grounding out'' to the body/frame somewhere. Although, THAT might cause a fuse to blow initially.

Speedometer stopped working & ABS light came ON. Also, CRUISE CONTROL won't work!

USUALLY the "fix" is to replace the ABS/SPEEDO sensor ($15) located on top of differential. OR, replace the sensor connector plug end at the differential end of wiring harness.

HOWEVER, this time it turned out to be a BROKEN WIRE in the wiring harness btwn. the differential sensor & where the harness plugs into cab directly under drivers seat (underneath the cab). There are 2 wires... a RED one & a GREEN w/black stripe one. I did a continuity test of the TWO sensor wires... AT the sensor plug pigtail & where the harness plugs in underneath the cabs' driver seat. ONE wire (GREEN w/black stripe) showed no continuity= broken (chafed) wire in harness where it runs btwn. the fuel tank & frame rail.

I ran a NEW/separate wire alongside the harness & spliced it in at the sensor plug & underneath the cab connection. PROBLEM SOLVED!

CAUTION: If this happens to you while you are on the interstate using CRUISE CONTROL.... the cruise control will STOP WORKING!! It startles you at first, as you think the ENGINE has a major problem!!