Sears sells a Fluke that has autorange [alot of the Flukes have this], where you just select ac or dc and it figures out the rest. They're about $100, I've had mine 8yrs still works great.
If you are checking for amperage/amperes/amps (all the same) then you would use the 10A plug in...
for voltage use the other one....it should be common knowledge by most that nearly all jeeps run on a 12 vdc system.... up to 14.2 vdc when the vehicle is running.
