[b3lha]

Does the car have an automatic gearbox? If so, is it behaving normally when the speedo is dead? Are there any warning lights to indicate that the TCU and ECU have lost the signal from the speed sensor? Flashing Power Light? Check Engine Light?

I assume that the 99 Legacy uses an electronic system like the SVX. If the failure is at the sensor end, the ECU and TCU should complain when they don't get a signal. If the ECU and TCU are happy then the problem is most likely at the speedo end.

Someone in the UK had a similar problem that turned out to be just a bad connection at the back of the speedo:

http://www.subaru-svx.net/forum/showthread.php?t=12278