1993 E-150 won't start and gauges/everything else won't turn on. I checked all the fuses in the car and non were blown. When I checked the relays in the engine bay they would blow when the engine was being started. The battery and starter have been tested and are in good working order. I think there's a short somewhere in the engine harness but have no clue were. I recently pulled the trans to change the rear main seal and the trans gasket/filter, could I have some how created a short while reinstalling the transmission? Any help would be greatly appreciated!

 

You lost me when you said the relays blow.
Did you check the wiring to see if you caught one of the harnesses in the process of bolting up the trans?