Just bought my first Volvo yesterday, a Black 940 GLE Turbo. It has 240,000 miles on it, but with a completely rebuilt engine and transmission. And the speedometer stopped working. Well, actually, it didn't stop working completely. It is on zero most of the time, but every once in a while, it jumps up to the correct speed. But then it falls back down to zero and stays put. 98% of the time it's on zero.
Anyone have this problem before? Any help would be greatly appreciated.

 

In the rear diff. cover there should be a sensor with 2 wires going to it.Yhat is the speed sensor for the ABS and for the speedometer.

Check the wiring first then check the sensor.

 

I checked that sensor by the diff cover, seems to be fine. Actually, very clean and tightly connected. I think the speedometer itself is broken. I used a digital volt meter and found that the 4-pin connector behind the speedo is getting plenty of electricity. But the speedo itself seems to just be dead.
It's gonna be a PITA to find a 940 Turbo speedo cluster around here.

 

Good luck!!!

 

Aloha everyone. I just bought a '92 940 Turbo and I have the same problem as mentioned in this post - the speedometer is intermittant. It will be working and then it will drop to zero and then maybe a few minutes later it will start working again. Same symptoms as in the original post. I will check my rear differential and the connection there, but in the meantime... I am interested in finding out weather the solution to the problem was discovered, and how it was fixed, by zysoclaplem.
Any help would be greatly appreciated. Mahalo, MikeO

 

I also have a '92 940 turbo and have the exact same problem. Speedo works up to 40-70 mph, starts to fall and then stops working. Please let me know if you figured out how to fix it.