4hi 4lo 4x4 lights flashing simultaneously

This is a fairly new truck for me. Great condition. However when I tried to activate 4hi (not for the first time; I do it often) both lights started flashing. It doesn’t seem to be in 4 but I can’t 100% tell. Any idea what’s going on?

 

I highly recommend walking through the first two replies of this thread before you get started: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

It contains everything you need to know about your new truck BEFORE you start diving in on fixing things. Because there are some very well known issues with these trucks you'll want to focus on FIRST before you spend any money on something that isn't safe to drive, or is at risk of major catastrophe in the short term.

Once you give that a whirl, and you've checked the bigger-fish-to-fry in that thread like the frame and timing belt and lower balljoints which can kill your truck as soon as today, here's a comprehensive guide on how to diagnose/repair 4WD in our trucks.