Flashing 4WD + no interior lights + no rear wiper! - something common for all circuit

[Serge]

Last month my 1996 xl Explorer got service engine light and dillership found bad oxigen sensor. OK, they replased it. After a week or two, interior lights start acting weird - they stoped working and at the same time 4WD flashes 6 times every 2 minutes plus rear wiper not moving. Sometimes everything went back and worked fine, but not any more. Now its permanent. So, I do not have 4WD auto or low, flashing 4WD and low 4WD no interior light, hood light, rear wiper - there might be some common problem for all of this, but I do not have electrical schematic for my explorer, and do not like to go to their service - all my problems happened AFTER service, so I don't want more troubles.
Can anybody give me an advice?
Thanks

 

[mdrut]

check fuses, one could have worked loose, also check the main fuse block under the hood, one could have some corrosion on it..

 

[Serge]

Unfortunately, all fuses and contacts are fine... Serge