middle position when you turn it on.(do your best to make it level)
Accel/Gforce will alternate back n forth.
Push the switch in to select one of the functions. When you select Accel you can calculate 0-60, 60-0 & 1/4 mile
After you press it a decimal number will show up. get it as close to .00 as you can. anything up to .5 should be able to zero itself out.
push the switch in again & the counter will zero out & will flash "Go"
If you want to test 0-60 only. when it flashes you 0-60 time. decelerate to below 30mph before you travel a 1/4 mile.
same in reverse applies to 60-0. somehow the GTECH knows when you're @ 60 so you dont have to be @ go to run that test.
for the quarter mile. its all the same just accellerate till it flashes your 1/4 mile time.