Thank you for answering my plea. The pump is getting power, and will operate the roll bar. But the power signal to the solenoid on the pump that routes fluid to the other solenoid banks (for the various top cyl.) is absent. So I hooked up a separate 12v supply to that solenoid. But I still can't make the top cyl. work and cycle. I was thinking that maybe the system was air bound; does this need to be bled, and if so, how? The manual doesn't mention any particular steps, just remove the old cyl. and install the new. I was going to separately inject fluid into the cyl., put the tubes back in, and manually operate the components so that maybe the fluid frim the cyl. will get back in the lines sufficiently to allow it to work. Am I on the right track? Or is ther a better way? The thing worked fine before I removed the cyl. (except that the cyl. were leaking), so I wouldn't think that the computer is bad. Are rebuilt ones available? Thanks in advance for any help.