The sensors are Hall effect devices. They do not directly contact the wheel components. The vibrations set up by the squealing brakes may produce ABS oddities. Also, if they are not properly positioned, they will give incorrect information to the ABS computer. I hope they didn't pry on them whilst trying to get the rotors off. Beware...

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Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.