ford lights

   I have a motor home on a 95 Ford E350 chassi and i need a wiring diagram for the lights.I have head lights front park lights,and turn signals front and back but no rear taillights ,markerlights,or brake lights.Checked all fuses with testlight all checked ok, since fuse box is not defined .Their was a time that they would come back on for a while or until you shut them off again leading me to think it was a relay problem but their's only 2 realays on the vehicle that i can find.Any help would be appreciated.

Rotate all the same sized fuses (despite them testing ok).

Those are 2 separate circuits.  Chances are the problem is going to be where those circuits are common.  Check connections at the lamps. 

Check for power at the sockets, if you have power than your ground is the most likely culpritThis information is provided only as a reference.

All circuits should be verified with a digital multi-meter prior to making any connections.

I didnt take the time to see if your vehicle is listed... Mr. I found this resource. https://www.fleet.ford.com/maintenance/owners_manuals/default.asp You can get owners manual that will have the fuse box diagram... Just thought i would add this.M.E.C.P & First-Class

Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!

 Thanks to everyone whom replied.I still havn't solved the problem but im working on it a litttle everyday.So far all fuses have been verified grounds have been checked and the light switch has been checked to no avail.The strange thing is I back fed the system through one of the marker lights and all the marker lights worked and the rear taillights worked but not the front parklights which lead me to beleive that they maybe 2 diffrent circuits,or theirs a problem were the front and back junction at.I looked at the Ford web site as suggested and all i was able to locate was info on the fuse boxes info on the wiring diagrams wasn't offered without Ford creditals.

Motorhomes on E350's are built on "cutaway" chassis. Ford runs the rear lighting wiring harness to the rear of the frame, and bundles it up. The coach-builder is responsible for providing the rear lights, and interfacing their lighting equipment to the Ford harness. Get under there, probably on the LR side, and find where the wiring runs from the frame up into the coach. Try to find the splices. That's where I would begin, based on symptoms described.