[Jon Skagfeld]

It's strange that you would find white/blue and red/blue on the same tailgate.

White over blue indicates the Unit Sign for a Signals vehicle, Red over blue indicates the Unit sign for an Artillery vehicle.

I can't imagine the both of them being on any Canadian Army vehicle at the same time!

There are publications showing colour plates for Canadian Army Units/Formations, notably Barry Beldham's extensive production of same, but I suggest that those publications would be more than your needs.

If you want info on the markings for your specific vehicle type, just keep on asking in here. You're sure to get an answer.