55C4 - No Message from DSC

The dreaded 4x4 light came on so I took it in to my local shop. Code reader first gave us a D35B No message (DSC sensor OCB) message. Supposedly the steering angle sensor was bad so it was replaced. Now we're getting the 55C4 error code. Shop tells me the DSC module must be replaced to the tune of $1400. I've searched and found that the DSC/ABS module can be rebuilt for much less and as I think about it, I'd rather go down this road. The module is supposed to be located behind the headlight assembly. So which one? Do I have to remove the bumper to remove the headlight?

Thanks in advance.