Hi Alan, 

Thank you for using our community 

The white wire is connected to the alternator of the device to count the hours. 

The red and blue wire is connected to the power supply of the machine which will charge the internal battery of the device with the right amount of voltage - more specifically between 12V-48V.

You can find more information about the installation of your raw device here on our Help Center: https://help.trackunit.com/en/articles/145493-how-do-i-install-a-raw-device
Or use our community guide here: 

If you have any further questions, please let me know 

I wish you a lovely Monday ahead!