ok I have a 2004 f250 I have replace every relay fuse even the switch still no turn signals I can ground out the wire on the switch does any one know where I can get a complete wiring harness diagram for this ive chased every wire I can find im missing something somewhere

 

I only have access to engine schematics. You may have to crawl the truck checking all wireing. Check the squirrels nest of harness&plugs behind the back bumper.

You did check the bulb right.

 

yes I have replaced all bulbs just in case one might be going bad I just need to know where all the grounds are

 

All lights are body ground. Corrosion issues are common.

 

my 4 ways work just right or left signals don't im stumped

 

R&L turnsignals have their own fuse but you said you checked that all ready.

 

Had the same problem including my heated seats. Happened to be a fuse that I had already checked but obviously not good enough.