I got to spend a little time reading the service manual and going over the S10. I did the two hydraulic tests listed in the service manual, using a paperclip in the plug under the seat. Definitely need to have battery at max charge to do this. I had to stop a few times to hook the battery back up to the tender as I wanted to cycle it numerous times. I checked for error codes and got 11,25, and 73. The FSM says 11,25 will be error codes when the rear wheel moves and the front does not, such as when its running on the center stand. I have done this before so I cleared the error codes and started over. At first no error codes, then 73 popped again. I took it out for a ride and really pounded the brakes. ABS functioned great over about 20 hard stops and was functioning fine. Just before I got home, I did one more for giggles and the ABS worked but the light came on. I turned key off, then on again and could not replicate the problem or get the ABS light to come back on. Fault code 73 states there's a pressure issue in the rear brakes between the caliper and master cylinder. I did not rebuilt the rear master cylinder and will order a kit to do so. I think that's gonna be the issue, we will see.