Here's what I've got. 05 LC, Marks PT kit with factory CDL, no diff locks. When I press the CDL I get VSC Off light and CDL lock light. There is another light in between those light that is TRAC VSC. When I bought the truck that TRAC VSC light would also be on when I hit CDL, so all three lights on in a row, is this true for others? That is no longer the case after the PT kit. Now with CDL locked and the VSC off in 4HI I still have TRAC interfering with my power. I would like to be able to turn TRAC off entirely but not off for good since my wife drives the truck too and TRAC is hooked into ABS and I'd like that on for most daily driving. Having TRAC off when you're in RWD is fun, the rear end can get totally wild.
Solution, pull the ABS switch on the brake MC. There are 2 or three sensors/switches on the MC and reservoir, the ABS is one of them. When this switch is pulled the ABS light comes on (so no ABS) the TRAC VSC is on (so no TRAC at all, obviously because TRAC is tied to ABS) and the VSC light is on so you can go sideways and the truck won't interfere. Of course I don't want to be under my hood every time I want to do donuts so all I need to do is splice in a switch to the ABS sensor and run a toggle into the cabin so I can flip that ABS whenever I want. I read this somewhere else, I can't remember where so I can't give proper credit where it is due. But I did test this just now in a packed snow parking lot and with the ABS switch pulled the truck has zero electronic interference, it's purely mechanical and you can slid it sideways, donuts, burn your tire, etc.
I think that the TRAC VSC is supposed to go off automatically when the CDL is on but for some reason mine does not go off. Maybe this is due to the PT kit, maybe it's just something wrong with my truck, or maybe I'm entirely wrong and it's supposed to just be VSC and CDL and the TRAC VSC is not supposed to come on. Thoughts on that appreciated. I'm minimally mechanically inclined, I know just enough about my LC to be dangerous.