It's an electronic program that works with the ABS. I would think it would need a software fix. Why not turn it off and do a manual "hill assist" with the LL, by holding the button as you come off the clutch and release. Please tell me that you have a momentary switch on the lock and not a maintained! I have seen some guys wire it with a maintained and that seems incredibly unsafe to me. I don't have any experience at this just a thought. One of the guys with a LL I am sure will chime in.
I dont have a LL, I am just thinking about installing one, but the hill assist already does this function, so I would rather mod that feature and be less intrusive into the braking system. I think somewhere in the hill assist there has to be a solenoid that momentarily locks the brakes... when you are on a hill. Find that solenoid, and run a momentary switch to it and bam, you'd have a LL.
If the brakes are controlled by software that is scary... I like to think that when I push the pedal, it directly pushes fliud down the lines, I can handle an electronic throttle, but brakes no way!!
I guess I need a wiring diagram and/or service manual for the car, where can I get one?
Sorry to burst your bubble, but as with the throttle, you are a voting member of the braking system. The ABS and ESP programs will exert control and will apply more or less braking as it see's fit based on your input. It, coupled with the ESP system is pretty amazing technology.
I drove the hell out of their cars at the SRT experience in a driving rain on the road course and did nearly everything in my power to spin it out but every time I got out of shape the ESP snapped the car straight again. If you have not experienced it, it is simply amazing. Most cars have this in some way, but the system on these is developed from M-B and is among the best in the world. Doesn't do you much good if it's turned off though