It was the speed sensor. I bought a new one and just finished installing it. Speedometer works as it did before, and no more HICAS light. I guess if the speedo doesn't work and the HICAS light is on, it's the speed sensor and not in the speedometer itself (at least in my case). Another victory! Sorry, I have to relish in them when I can, because I still can't figure out why the stock alarm isn't working (and it has been over a year now).