2009 Peterbilt 386 Dome lights help

I am a little new to the Peterbilt family so bear with me. I am in a 2009 Pete 386 with a Cummins ISX. It is a fun truck, but...

My dome lights don't work. When the door opens I get nothing, and when I turn it on I get nothing. This is on all of the dome lights, above the driver seat, passenger seat, center, and under the cup holder/ash tray. Sleeper lights work just fine. I went straight to the fuse box and started my search. There were a few old corroded fuses, replaced them and still got nothing. Checked the battery box and found a little bit of corrosion but not too bad. Cleaned them anyway and reattached everything with no change in my situation. I have read other posts about the "Low Voltage Disconnect." I am not sure where to find this elusive animal. Any help would be greatly helpful and appreciated. Also any other suggestions you may have are worth looking into. Thank you for your time and interest in my problem today.

 

Thank you a ton. I will look into this over the weekend. I have tried some of the other things as well. Relays are all looking good, bunk fuses look good. Door switches are next, I will let you know what I come up with.

 

Okay, picked up the new door switches today, got them installed. No luck. It does appear that the old ones had a bunch of corrosion and needed some attention anyway. Just wish this was the cure. Any idea's?