I recently bought a 1989 Mitsubishi Montero 4DR. Everything works great, except that the wheel lock light is always on . It would be great if this was an electrical malfunction but it is not. I know that the wheels are locked and sometimes at least one disengages and I hear a grinding noise coming from one of the tires. The only way the noise goes away is if I come to a complete stop and at that moment the wheel lock light turns off and on and I hear a clunk noise. Does anybody know what could be causing this and how to possibly fix this problem?

P.s.
I am new to the four-wheelin world and to this site.