Volvo: Speedometor, volvo s70, failure rate

Question
I have a 1998 Volvo S70. My speedometer keeps acting up. Sometimes it will work fine. other times, for instance if I am at a traffic light, when I go to accelerate from being stopped, it won't work. Sometimes I can turn the car off and then back on again and it will once again begin working. Sometimes it won't though. Do you have any idea if this is the actual speedometer or could it be electrical? Any ideas?

Answer
Nichole,
The ABS control unit also uses the speed signal and when it goes bad the signal will not make it to the dash cluster. Read any codes for the ABS. They (control unit) have a high failure rate. If there are codes, a replacement may fix both problems.