windshield wipers not working

Nancy Lambert before testing the actual motor you want to check a few other things. Start of by checking the fuse for the wiper, make sure that you have continuity. If that is okay you want to check the switch and the relay. Make sure that you have power on there. Lastly you can check to see if the motor gets power. If it does and does not work, you'll know it has failed. Start step-by-step with something like this. not quite your model but it should come pretty close. Good discussion about Cadillac's wipers on here and might be useful.

If you do need to work on your wiper/washer system, this part of the manual should be helpful Cadillac Deville Wiper_Washer System