yeah the mechanic is right, cars no good, I'll give a a buck fifty!

Call up your local bbb or someone in DA's office and explain to them that this guy is ripping you off (veriy first ofcourse). Get away from that mechanic ASAP. Get a second opinion. Go to a volvo dealer, even they have some decency on ripping off people.

He may be somewhat right about the motor mounts failing and causing the short.

The cable (2- and 1+ wires) runs from the battery under the cross member to the drivers side. One short (- wire) runs to the body frame, and the other (- wire) to the engine underneath. The positive wire, also runs with the - wire to the engine, goes under the cross member. But (+) this goes over the cross member on the drivers side. This wire (+), runs next to motor mount and ends at the starter solenoid. It is held in a bracket, and that bracket is attacted one of the drivers side motor mount bolts. Worst case, I think in your car, the engine is hanging and may have crushed the + wire and caused a short. Otherwise there may have been a short at the sway bay, with failed mounts. The engine touches the sway bar. Both cases are very very rare.

As far a damage, all circuits are designed with fuses. I don't see any damage to the any sensors or ecu.

What heck is he replacing for $4700? Every sensor and wire in the car? No way.

Do tell how it turns out.

Nothing to figure out. Dishonest mechanic.

There are 2 or 3 battery cables. Look under the hood and you will see where they go. One goes to the starter, one goes to the fuse box and one goes to ground. None of these would be affected by bad motor mounts. They are cheap and easy to replace. However there are many other cables in the car which would not be described as battery cables. Which cable is affected. Suggest you have this "mechanic" show and explain exactly what is wrong, give you a list of parts and prices and break down the labor charge. If I was considering spending those bucks I would want a second and third opinion. Please post back what you find out.

PS I will give you much more for the car and pay the towing to North Carolina.

dude if its the battery cable only shit replace it its a 5 dollar part at the store and easy easy to replace. if the care doesnt work then start looking at your wire harness, in the worst case you may have taken the computer with the short but that is rare alone with a batt short and the computer shouldnt cost you anymore then 1 g new and 45 bucks used on e-bay. the harness you can get used for about 150 from any junk yard tha has them or new for about 300 a pop. so he is pretty much ripping you off BIG TIME. if every electrical part i mean them all went out your looken at that price but theres no way in hell every part went out it is impossible since when something like that happend everything goes through the fuse box first and thats where it would be stopped thats why it is there, if your engine mounts are bad i dont think it would cost more then a grand period at the most to have those replace it only cost me 300 hun to have my tranny mounts redone.