tail lights stay on when truck is off

Hi @kergan29 ,

Are you sure that it is only the tail lights and not the license plate lights and the front parking lights as well?

Here's an image taken from the 2003 Tundra service manual and it shows that all the above mentioned lights are on the same power feed from the integration relay.

According to this link, Post #5 states "...the integration relay being located in the junction block just below the fuse panel at the lower left dash panel and post #9 states "...the integration relay is actually the circuit board behind the fuses."

It seems that the problem may be in the integration relay circuit for the tail light as the lights should turn off even if the taillight switch is on, with the ignition off and the driver's door is open.

(click on images to enlarge)