Unfortunately a lot of folks with early versions of the Harley ABS have been bitten by defective ABS pump and valve assemblies. Harley tells everyone it's a failure caused by old brake fluid, but that's pretty much BS. The problem is caused by the materials used in the valves, which easily corrodes and then sticks. The auto industry does not have this problem, and none of the manufacturers I'm familiar with require a full fluid change every couple years like Harley is now recommending. In fact, most cars don't require fluid flushing and replacement until the system is opened up for other repairs. But if you're running Harley ABS you need to heed their warning and change the fluid regularly, since we have no way of knowing if they ever fixed the corrosion problem with their system.
One thing about the early version that doesn't help the repair cost is how Harley only made the pump and electronic control module available as a complete unit. In most cases both parts don't need to be changed. I was under the impression they only had the single part number for the entire system in the first year (2008), and switched to the separate part numbers for 2009.

The pump and valve assembly runs about $450 - $500 last time I checked (doesn't include the electronic module). If you also replace the electronic control unit then you're probably looking at something close to a grand just for the two parts.
Jerry