I'm not sure about the 1999 but I have a 2000 Rodeo so there can't be that much difference. What you have to do is remove the skid plate; very easy to do. There are only 5 bolts to take off. The oil plug is located toward the rear, about half way back. The plug faces the rear of the vehicle so you may have to feel around for it.
Where is the oil dran plug on cadillac deville, 1999
It is on the oil pan towards the back.
Oil pan.
oil filter is located on the engine block under the car. drain plug is located on the oil pan.
It is in the bottom side of the oil pan.
on the bottom of the oil pan
The oil drain plug on a 1999 Dyna Wide Glide is located on the bottom of the engine. It is on the right side of the engine.
in the botton of the oil pan
Should be at the rear or side of the oil pan
Oil drain plug is in the pan You probably have to remove a shield that hides the plug to access it 7/8's wrench to remove plug 14mm socket to remove skid plates
14mm
On the bottom of the oilpan