Can you tell me if alignment lifts are level? .. or are they supposed to be?
There's nothing in the FSM about what to do with AHC at time of alignment, but I've always wondered about turning off AHC before handing over the keys to the shop, or telling them to let it level out once its raised up on the lift.
My alignment lift is specifically made for big trucks, its max weight is 12000lbs. It is very long and it is a 4 post. I would never take my car to alignment shop that has a scissor lift OR a parallelogram. I have had a lot of issues in the past with those which caused alignment hell.
My machine is a John Bean (snap on) aligner. The software tells you exactly what to do and gives measurements as to where to measure for proper height. After the height is measured the aligner takes those measurements and gives you data points as to how to align the vehicle.
I honestly believe that my issue are the tires. If i had brand new tires i don't believe i would have had this issue.
AHC - I don't believe by turning it off or raising it up or down will change anything BUT misalign the vehicle. Reason being the vehicle will have it on and will adjust height constantly during your drive. I did raise the vehicle when i adjusted my caster to really push the tires forward for my 33's. This only changed during the caster and when i did the alignment it was off per the toe being in a raised position when i adjusted it.