@tonygurney , I am assuming that you are using the ESC hardware version M0134 (you can confirm using voxl-esc scan tool.
Here is the datasheet for M0134.
https://docs.modalai.com/modal-esc-datasheet/
This ESC has an option (via installing a 0 ohm resistor) to provide 3.3V to pin 1 of J3. This is the same voltage that is used for the MCUs that run on the ESC and should be used with caution (if this voltage rail is brought down by overloading, the ESC will shut down). Please see image below that shows where 0 ohm resistor should be (carefully) installed to enable 3.3V on pin1 of J3 (marked in red)
m0134-diagram.jpg
If you actually wanted 5V (VAUX), that is available on the other side of the board via two test points at the edge of the board. This voltage rail is provided by a separate switching regulator. See the following section : https://docs.modalai.com/modal-esc-datasheet/#neopixel-led-support
If you REALLY need 5V to be present on pin1 of J3, then you can add a small wire jumper from the VAUX test point directly to the pin1 of J3 (which is marked with a white dot). This pin 1 of J3 is normally disconnected. Please only do this if you are comfortable performing this type of soldering and we cannot guarantee the results :).
Alex