I have a 2001 Disco 2. I got it 6 months ago, and the cruise has never worked. I have checked all hoses. When I press the cruise button, the light illuminates. When I try to engage the cruise, it holds for a brief moment, then slows down. I disconnected a vacuum hose at the pump, and manually engaged the vacuum diafram and it held when i plugged the hose. Could this be a bum cruise pump?