I just bought a used 2001 Ford cargo van
On the back bumper, just to the side of the license plate, is a little nozzle, looks just like the valve stem on my tires.
What is it for?
Air shocks?
Air shocks. That’s a schrader valve to add or subtract the shock load.
Yes, definitely air shocks. I just had air shocks added to my van for towing.
Next time you have the van serviced you should get them checked to make sure they’re inflating / deflating properly. It is also worthwhile to see if your mechanic can determine the extra load capacity they give you since there are different types out there,
You should also keep them deflated if you don’t need the extra weight capacity in your hauling. Mine significantly alters the ride when I’m not hauling a trailer. They make my van handle like a barge.
note that air shocks are not license to overload your vehicle. the shock mounts are not really meant to be load-carrying.