I didn't use the blue wire either, and mine works just fine.

Since your car didn't have factory cruise, I assume you used the switch that came with the kit? I believe it has a green light on it that will show when/if the power is on. Does your green light come on?

I guess a couple of things I'd check would be the brake switch (make sure it's not cancelling the cruise) and the speed sensor (make sure it's got the correct gap between the magnets and sensor).

Outside of that, just recheck every connection, make sure you have good vacuum, the linkage is hooked up to where it pulls straight, etc.

Was there a phone-help number in the Audiovox box? It seems like they do offer troubleshooting assistance.

Good Luck!
Russ