Nooby, I'm not convinced the controller is set at 48V, as you have already had it running on 24V.
You should be able to carry out a simple test to see if the throttle circuit on the motor side is OK by connecting a small piece of wire
(reshaped paper clips work well for this) between pins no 4 and 6 on the 8 pin motor socket which should make the motor run at full speed:
Make sure the wheel is raised off the ground and that the power is turned on before you insert the wire.Be very careful to only put it into the correct holes or you could damage the controller or wiring.
This diagram shows the wiring on my early Magic Pie, but as least it shows where contacts 4 and 6 are located:
Click image to view full size.
If the motor spins, this would indicate that the speed controller and the motor wiring harness are OK.
If this works as expected, remove the wire and plug the main wiring harness back in, and then repeat the same test, but use the red and white wire connections on the throttle connector instead.
If the motor does not spin when 4 and 6 are linked, it could be due to a controller fault or a break
(or short) somewhere along the thin red wire which runs between the controller and the socket.
With the throttle disconnected, the motor should run at half speed when you connect the cruise control wires together with a wire link.
Let us know what you find.
whereaboutsdo you live, or did I miss that in the post ??
Ginge, it was mentioned earlier, but I'll give you a little clue to save you having to look back through the posts:
Alan