To test the parking brakes: Fasten safety belt, set parking brake, release trailer parking brake, Place vehicle into a low gear, gently pull forward against parking brake to make sure the parking brake holds. If it doesn't hold vehicle, it is faulty; get it fixed. / 测试驻车制动:系好安全带,拉起驻车制动,松开挂车驻车制动,挂入低挡,轻轻向前挪动以检验驻车制动是否牢靠。如车辆仍能移动,解释故障应立即检修。