Any suggestions as to what to test and where to place the multimeter probes to help diagnose the problem?
This should help:
With everything connected up as normal and power turned on, push the negative
(Black) probe on your voltmeter into the rear or the pedelec connector where the black wire goes in.
Select a suitable voltage range on your meter to cope with battery voltage and then test the cruise control signal voltage using the Positive
(Red) Probe on the signal wire going into the rear of the cruise control connector.
My Pie's harness has a Black ground wire and a Grey cruise signal wire, I measured ~28V
(using 29.4V battery) on the Grey wire, and this reading drops to 0V when the cruise button is pressed.
If you can't detect a high voltage reading on the Grey cruise signal wire, you will need to take the wheel off and remove the freewheel side cover to gain access to the controller connections to be able to check the continuity of the grey wire between the controller connection and the cruise button connector. If this wire is broken, it might be possible to use another wire within the cable instead.
The pedelec signal wire can be used if you're not using pedelec, or the yellow lead which is used for reverse and/or programming, can be used if you don't need to use the program interface cable or the reverse function.
If you have a high voltage reading, but it doesn't drop when the cruise button is pressed, check the voltage on the Black wire. If the voltage on the black wire is high when the button is pressed, the switch is working fine, but you will have a fault somewhere on the black wire
(ground connection) which daisy chains across several of the connectors on the main wiring harness. With the button pressed, check the voltage at each of these connections in turn to try and pinpoint the faulty connection.
Alan
