Abs, brake won't go off, fluid full, just changed rear rotors and pads and rear brake line. also, trac light flashes on and off. how do i reset this now that it is fixed? car is a 2002 lexus is300

The ABS system and TRAC system are very similar. Signals from the speed sensors in the wheel hubs and one on the output shaft of the transmission are checked against each other. If when you apply the brake a wheel is detected as running much slower than the others brake fluid is relieved from this wheel to stop it skidding. Likewise when you accelerate the speed sensors detect a wheel speeding up faster than the rest and the brake is applied to it to gain traction control. So you can see that the speed sensor operation and their signals are central to both ABS and TRAC. If you have a problem with one then you invariably have a problem with the other. You need to check that the speed sensors to the wheel hubs are intact, that the connections are good and that the wiring has continuity. Also check the speed sensor on the side of the output shaft on the transmission casing, the connection and continuity. If any part is loose this will be enough to upset the complete system.