I had the electrical instrument harness cluster.

I had the electrical instrument harness cluster replaced in the steering column. Now the ABS light stays on when the engine is running. When the ABS light (on the dash board) is on, the blower fan will not work. NO a/c, no heat. Sometimes if I hit a bump in the road, the light will go off and I can turn on the a/c.
I don't know if this problem is a result of the replacement, or a different problem caused by something else. No one has been able to figure it out. I am hoping someone out there with vast experience can help me with this question, have some pointers or good guesses that I can pass on to my mechanic. Thanks to all of you for giving this question consideration.