2nd gen trailer brake controller

Hi. I’ e got a 2012 single cab with bench seat. TRD. SR5
It has + - gain on the shift controller next to the Tow/Haul mode button.
The gain doesn’t seem to do anything. Has anyone figured out how this works?
Thanks in advance.

 

That's to manually set the max trans gear when in "S." Helpful when downshifting while towing.

 

When you pull the shifter down and in past drive check the gear indicator - it should read 4.
Not D. That button allows manual shifting of gears at that point. It helps when in Tow/Haul mode
but lots of guys just shift manual all the time. It’s nice downhill in construction to save brakes!

yer dash is filthy, clean that up! LOL.

 

That's how you shift.

If you have a brake controller (unlikely it sounds like) it would be just right of your right knee, if you don't have it then there will be a little cubby spot.