Front Wiper not working

[tom_h]

Hello I'm new here....
I'm trying to fix a my front wipers which stopped working.

I took to a garage and they said it was the motor and said they could order and replace.
The next they phoned and said actually they can't get the motor and I would have to contact VW.

So having had a diagnostic that the motor was shot, I found a second had one and replaced it......no change.....still doesn't work

I'm now thinking that perhaps the garage didn't check properly and there is an electrical fault (or else I have bought a broken motor)

Can anyone help with diagnostics?
I have checked the voltage to the connection at the motor and I have 12V (across the 2 larger diameter wires).
I have this even when the key is not is the ignition, so I'm looking for guidance on what to do next, to locate the source of the problem.

Could someone talk me through what readings I should be getting at the connector on the wiper motor with the ignition on / off / wipers on etc

Is there are way to check that the 3rd smaller diameter (data) cable is providing the correct voltage?
Is there a way to check the motor?

Thanks in advance for any help
Tom