Ugh. My Tacoma was like that! Locker only worked in 4 low. The most frustrating part was knowing the 2wd "prerunner" models had a locker which, obviously, didn't require 4wd to operate. WTF Toyota?? I ended up splicing in a relay to bypass that, and let the locker work anytime. I was happy to see I didn't need to do the same on the F150.

 

I've only tested my locking diff to see if it works as well. It's good for doing donuts in the snow.

I did try hill descent today and it worked very well. I tried hill descent on a 2016 hyundai Santa Fe I had for rental on Titus canyon Rd going into death valley and everytime I turned it in it sounded like something was going to break. Awful noises. The descent control on this f150 was smooth and quiet. All I had to do was steer.

 

That's the same way my Frontier was. I was going to re-wire the locker like you did, but then my diff grenaded on me so instead I installed a Detroit Truetrac. Best mod I ever did to my truck, it was good enough that it could act like a locker when one wheel in mud and the other on solid ground, but still mild enough to work fine in daily driving on the streets.

 

I really don't understand why companies limited them to 4wd mode on 4wd trucks, but will install them on 2wd truck. Makes no damn sense to me. I probably would have had to go your route had I not traded the Tacoma since the actuator corroded through preventing me from making the locker work. I stripped it down, cleaned it, got it functioning again, but it stopped once it was all bolted together. Could have been too much material patching the hole, who knows. It was something like $1200 to replace that part (dealer only, of course) so it wasn't worth fixing beyond my redneck patch job. lol (hot melt glue to fill the gaping hole in the casing)

So far the traction control on the F150 has prevented me from needing the locker just to stop that 1 wheel from spinning in 2wd mode. And I'm just amazed by that. Such a difference between that, and the open diff, no TC, Tacoma!

 

My Frontier had electronic traction control too but I wasn't impressed with it. It worked fine at slow speeds, but if you were in a situation where you needed some wheel spin (like in the mud to keep the treads clean) the T/C would apply the brakes so hard to the spinning wheel that it would stop all wheel spin and you'd be stuck, literally.

 

So far I have liked the T/C options on the F150. I played a little in the snow, and could get some wheel spin in the various modes. Probably advance trac sport mode or whatever it's called.