That indeed is a strange one!

But since these problems started right after you changed the relay under the dash, I'd start there. Double check to insure that you installed the relay correctly, and double check to insure tht you used the correct replacement relay. If you are CERTAIN that both are correct, then I would consider the possibility that you disturbed something under the dash when you were under there changing the relay. You may have broken a connection, or shorted a couple of wires there were worn bare, or something of that sort.

1977 CJ-7, fiberglass body, AMC 360 w/ headers, DUI ignition, Edelbrock intake and Holley 4150 carb, TF999, Dana 300, 4.56 gears lockers, York air comp, 4" susp lift, 2" body lift, BFG 35" M-T tires, Megashifter, AGR pump & box, REP8000 winch.