Help needed with VSS wire

[somersetdub 0]

Hi, 

I am trying to ascertain why the speedo isn’t working on my ‘93 Vr6. 
Should the instrument cluster be supplying a 5v feed to the vss line?  I’m not getting any 5v feed on the vss (blue/white) wire. 
On the outer two pins on the vss plug I have ignition 12v and earth, which is correct, so the problem lies with the 5v feed. 
I managed to get the speedo to work by applying an external 5v to the vss wire, but I’d rather replace the cluster if it’s that which is the issue. 
 

[Philly-R6 0]

There are three pins on the Vehicle Speed Sensor:

1    Black    12v (Ignition)
2    White/Blue    Signal
3    Brown    0v

Pin 2 provides a square wave whose frequency changes with speed.

I found this video: VW VSS speed sensor 4 pulse - YouTube

I have never tested a speed sensor, so you may have to apply this to what the sensor looks like...

Essentially, take the sensor off.
Apply 12v to pin 1 & 0v to pin3.
Turn the gear inside the sensor and see if you get an output on pin2.

Have fun!

[somersetdub 0]

Thanks for the reply. 
I have already tested the vss wires - I’m getting a 12v ignition feed and earth on the outer two pins (black/brown).. what I’m missing is a 5v signal from the VSS wire. 
I have read on a couple of pages that the 5v reference should be coming from the instrument cluster, not the sensor itself. I’m trying to find out if this is definitely the case. If it is the case, I’m assuming my cluster is faulty. 
However, as I said, when an external 5v feed is applied to the VSS wire, the speedo then works- we turned the spare old VSS with a drill to replicate driving.