Need help with wipers, please.

[Gone Fishin']

Hey all, the wipers on my '02, 250, 7.3 quit a couple weeks ago. I have checked, fuses, relays, motor, switch. All good. I thought it was the switch and had to order one so I also ordered the motor assy. (motor & controller). I replaced the switch, still no go, hooked the new switch to the new motor, still no go. I tested the relay by removing it and applying 12v to the coil. They worked fine in my hand. I have been scratching my head for an answer. I am leaning towards a bad ground connection, but... Where would I find the ground connection for the relay bank? Also, where can I find schematics and diagrams for the wiring? Thanks for all your help. BTW, Happy Thanksgiving to all.

GF