Brake light and ABS light on. Any ideas what sensor may be causing this?

The ABS module would need to be scanned for the proper fault to repair.

Check brake fluid level.

Check the "tone rings" on each of the wheeels; these are rings that are pressed onto the drive shafts near the back side of the wheel hubs and they look like a ring-like gear with teeth about 3/32" apart. The rings are about 1/4" wide and the teeth are about 3/16 tall, total. The teeth are supposed to pass under a sensor near them and they will often crack/break so that the sensor sends a confusing signal to the computer which then tells you that the ABS is not working since the signals are jumbled by the difference in tooth spacing. A code-reader (OBDII) might tell you which wheel to look at; check the sensor, too, for broken or loose wires. Good luck.