2011 Volvo VNL 730 Inter axle light keeps flashing.

I have a 2011 Volvo VNL 730. Suddenly one day a single axle light with an x in the middle started flashing. I researched and found it’s the inter axle light. I don’t have an inter axle switch in my truck and it’s a tandem axle truck. Has anyone had this problem before. Sometimes it goes off on its own then suddenly pops back on.

 

Differential locks I’ve seen on all trucks. I’m not sure about an inter axle mechanism. Correct! It goes on and off when it chooses too. I’ve looked over every button in the truck several times. I even looked in manual and it only shows diagram of inter axle symbol.