electronic speedometer sensor 1976 911S

[nssnorm]

Is there away of bench testing speedometer electronic speed sonsor? I have 12 volts positive , I tried with multimeter,disconnecting ground and twin brown,red wires, no pulse,indvidually wires show continuity, do Ihave to test with 12V and broww,red,together + and ground- to get a pulse? also what is wire green/white wire doing?I would appreciat any help, Thanks Norm

[Flat6pac]

The pulse is derived from inside the transmission, just the inside from the sensor there is a disc with 8 magnets.
The magnets do fall out if youre any combination of 12.5% loss of speed on the dash, thats the problem.
If youre simply not picking the info up, the sensor on the trans isnt all that expensive but first make sure your wires are connected inside the tunnel access.
Bruce

[nssnorm]

Thanks Bruce, I do not understand about the 12.5 loss of speed at the dash, is this voltage?,so this indicates a new sensor is needed, please help, Thanks Norm