The windshield wiper relay switch, on your 1999 Cadillac Deville, are located mounted to the firewall in the engine compartment. The relay switch will be next to the windshield wiper motor.
The fuse is next to the parking brake. If it has a relay, its in the under hood relay box near the windshield wipers.
check the fuses and relays
Ignition Key switch is bad.
because it doesnt work
Windshield wipers don't work
Wiper park switch is bad
Why are there windshield wipers inside the car?
On the back of the engine right below the windshield wipers
Mary Anderson invented windshield wipers in 1903.
Replace the windshield wipers.
either under hood or in trunk on back of seat. may be a relay
I got the same problem did you ever find the problem