99 PSD doing funny things

[William2002F350]

This is one of my buddy's trucks and thought maybe you guys could help me out with trying to fix some issues.
Its F250 99 (12/98 don't know if that still an early 99 or late) ext-cab 4x4 Auto LB, bone stock. Previous owner installed cab lights and that's were it started.

The cab lights would quit working at times so we figured it was a ground issue,
then it started doing some funky stuff, be driving along and all the sudden the E brake light would flash and start dinging, even though the E-brake was not on,
then if you would get below 15mph the interior lights would come on, get over 15mph they would go off.
Take off from a dead stop truck would not shift to OD, slow down to 15-20 mph, accelerate back up and then it would shift to OD.
Cruise quit working.
Sounds like all electrical issues to me, but I'm a retard when it comes to wires and that stuff. Any help would be appreciated, Thanks