Headlight dimming problem

I have a 2014 Tacoma. The headlights have been working fine. Recently I noticed the bright headlight does not revert back to dim. The bright light indicator light in the truck instrument panel does turn off and on. If I turn the brights on initially, they do turn on and off. If I leave the brights on for a while they stay on until I shut the truck off. When I turn the truck back on, the brights are off. Any suggestions as to what is causing this. An electrical diagram of the headlights would be helpful. Thanks.

 

Sounds like a sticking relay.

 

I would swap the DIM Relay with a like relay and see what happens.

It could also be an issue with the Body ECU that controls the DIM Relay Coil Voltage.
The Body ECU is on the back side of the fuse panel behind the dash to the left of the steering wheel.



https://www.tacomaworld.com/threads/dome-light-flickering-on-door-mode.739767/#post-26338377



Back side of interior fuse box with the Body ECU Cover removed.

 

Where is the dim relay located? Thanks for your help. Will be easier to trouble shoot once I know where relay is.

 

One way to find which relay does want is to put your finger on them, turn it on, find the one that clicks. It’s easy to get this wrong. You’ll have a finger on one relay, the one next to it is clicking. Pull out the one you think is clicking, switch again and you’ll be able to figure it out.

 

The DIM Relay is in the underhood fuse/relay box.
The Body ECU controls the ground side of the relay.

Do you have stock bulbs or LED's/HID's?
Being your indicator works I'm suspecting you have aftermarket bulbs and something is wrong with them because the High Beam indicator is fed off the same wire that feeds the Left High Beam bulb.