Speedo+Odometer gone dead

HI Guys,

The speedometer and odometer on my Logan suddenly stopped working. A few days earlier, I ad some other problems, which were traced to some wires chewed off by a rat.

So now too, I am inclined to suspect the wire between the sensor and the dash to be broken. But the geniuses at the service center refuse to even consider that possibility, and insist the sensor needs to be replaced. And, to top it all, they do not even have it in stock.

I dont mind spending the money if that is genuinely required. But it would be absurd to replace the sensor if the problem is just a broken wire.

So my question is, has anybody had a similar problem? How does one get access to the speedo/Odo sensor? If that is known, I could trace the sire back myself, I am fairly comfortable with electronics.

And lastly, if the sensor does need to be replaced, is it available in the open market?

Any feedback would be highly appreciated.