Dear B.B.,

Hope you're well and stay so. If you can raise your car's tail-end, you'll find one or both of the wires, that connect the speedometer to speed sensor mounted in the differential cover, have corroded away. The wires are exposed to under-car hazards: water, snow-melt chemicals, etc.

To separate the wiring harness connector from the sensor's bullet-format terminals, I'd saturate the sensor's terminals with a corrosion-dissolver, e.g., Deoxit. Then, using a needle-nose pliers, with tips bent at 45°, grip one of the the female wiring harness terminals and - going very gently - try to turn it. It may take several saturations - over a few days - for the corrosion-dissolver to weaken the corrosion bond, to the point where gentle rotation with the pliers will break the corrosion bond.

Once you've removed the failed wiring harness terminal connectors, you need a short section of wiring, with female wiring terminals. I'd splice that to the wiring harness, first having slid sections of heat-shrink tubing onto the wiring harness. I'd then solder the replacement section of wire to the harness, and then apply heat to the heat-shrink tubing. I'd then wrap butyl rubber tapd around the rapaired section, to exclude water, salt, etc.

Butyl rubber tape - usually available at home improvement stores or auto glass shops - is very sticky, does not harden with time, and when compressed forms a leak-proof shield.

Before emplacing the replaced wiring harness connector onto the speed sensor's connectors, I'd apply a thin coat of di-electric (bulb) grease, to inhibit corrosion. I'd then wrap the top of the speed sensor in butyl rubber tape, to keep out water, salt, etc.

As to backing onto ramps, I got rid of ramps years ago. I disliked the idea of having to accelerate to get the car to move up the incline, and then having to hit the brakes to allow the tires to settle into the ramps "wells". I use floor jacks and jack stands to raise the car. This is slow but very safe. I never go under a car raised only with a jack.