Door Locks will not lock as exiting the vehicle

Bought a used 06 Tundra SR5 checked everything except the lock on exiting the vehicle..
It did not come with a fob. When you exit the vehicle and either hit the lock button or the actual lock it immediately unlocks. It will also not lock with the key from the outside. On the inside with the door closed it operates as normal. Any suggestions on where to start?

 

In my experience, if there is an issue with the left front door lock actuator, it will revert to unlock and unlock the rest with it. With it not allowing you to access the key from the exterior, I would start with the lock actuator assembly on the driver's door.

 

Adding to that, if there's anything preventing one or more door actuators from locking, it reverts the condition. For example, if your kid is holding the outside handle while unlocking, theirs will revert to lock. I've seen this happen from inside also.

That isn't limited to holding handles. If, for some reason, anything inside the door is binding and even if there's too much inward/outward pressure on the latch, it can fail to lock/open.

 

Oh, and programming instructions and a bunch of extra tips/things to check are over here: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

 

Being that it works fine when the door is closed, I'm wondering if for some reason it still thinks the key is in the ignition. This is a feature that prevents you from locking your key inside the truck. When you hit lock it will unlock itself so you can't lock them inside. Sometimes when these trucks get older you are able to remove the key without turning the ignition key hole all the way to the left. This means you might remove your key, but it still thinks your key is in the ignition since the key hole was not fullytuend back to the left. I would try making sure that you are turning the key hole completely to the left before removing it. This might be the issue.