99 Suburban cigarette lighter fuse
 

I have a 99 suburban that has recently started blowing fuses on the electrical circuit that powers the cigarette lighter. I tried replacing the fuse and it immediately blew. I disconnected the 3 cigarette lighter outlets and there is still a short somewhere. I found that the power door locks are also on this circuit. So I disconnected the two front door locks and the cargo lock switch. Still there is a short somewhere.

Does anyone know what other device is on this circuit? I looked in the lousy Chiltons service manual and they do not include the schematic on that circuit. I don't have an OEM manual, but I would think that there is a schematic that outlines what devices are on the circuit.

Please help......