if i were to guess i would say a bad ground at the headlight. what is happening is the turn signal and high beam are finding a ground through the low beam filiment and returning to ground through it.

sounds complicated i know but look under your car. try removing thoes lights affected. possibly the theives cut some wires under your car. for what reason i dont know unless they figured they could disable the alarm if they thought it was equipped.

best way to find the problem is look visually. then using a meter or test light test the curcuts with the lights on at each light. if you find a ground wire with power on it that would be the bad one.

good luck