As described, you need to cross the scales three times.
First time.
Fill the fuel tank and go the scales fully loaded like you are going camping. Find some scales here:
http://www.publicscaleslocator.comPull up on the scales with the truck front wheels on the first pad, the truck rear wheels on the second pad and the trailer wheels on the third pad. There is a button to push to call inside. Sometimes there is one low and one high. Sometimes there is only one high at the level of a semi truck window. I take a broom handle just in case to push the high button. You need to be in the cab of the truck when it is is weighed.
The operator will ask, "First weigh or reweigh?" You say, "First weigh".
The operator will ask, "Unit number?" You say "555" or whatever number you want to use.
The operator will say, "Got it!" or some such. You are already weighed. If you are standing outside the truck to reach the high button, none of your weight will be distributed to the rear axle on the second scale.
You pull off the scale, go park, and go inside to pay about $11. They will give you a weight ticket with a serial number on it.
Second time.
Release all the tension from the weight distribution bars. I take them off and put them in the back of the truck. Pull back on the scale as before. This time say, "Reweigh". The operator will ask, "Ticket number?" Read off the number on your ticket. Pull off the scale and go inside with your ticket number and pay $2 and get another ticket.
Third time.
Unhitch the camper. Remove the WDH and bars from the truck and leave them at the camper. Pull up on the scales with only the truck, front wheels on the first pad and rear wheels on the second pad. This time again say, "Reweigh" and give your ticket number. Pull off the scale and go inside with your ticket number to pay another $2.
Now you have three weight tickets. Now you can do some math and determine the following:
