It might be turned off. Look at the first post for instructions to turn it back on.
You do have to come to a complete stop on the hill, with your foot on the brake. Once you take your foot off the brake, HSA will only keep you stopped for a second or two before it releases. If you haven't gotten on the accelerator in time, or hard enough, you'll roll back even with it working.
And are you sure the hill is >8% slope?
He that would make his own liberty secure, must guard even his enemy from oppression; for if he violates this duty, he establishes a precedent that will reach to himself. --Thomas Paine
We work together every damn day. --Jon Stewart
Any gas can be a knockout gas, when you wrap a steel cylinder around it and beat someone with it.
Low Output 4 Cylinder Jeep Club member #188