I had the original factory acculift actuator and after a while I found it was very slow to the extent that I had to help it manually to even open the sundeck. So I concluded it was giving up and I went out and bought a new hardin marine from cp performance. Installed it and I still need to help it manually to open the sun deck. Now I'm clueless, what is wrong. Is there a factory relay that could have gone bad? Anyone with any ideas?

Does it hinge freely? Maybe problems with your hinges? Sun pad water logged and heavy?

The hinges move freely and the sun pad is raised all winter, so logged water should not be a problem. Also when I raise it now and let it stay up there is almost no water coming out of it.

Check both batteries

A relay is going to work or not work, no in between. Is your system a hydraulic system with a pump? What did you replace?

What did you find out...mine just went out yesterday. It was abnormally slow the other day and now it wont come up at all. I can hear the motor spinning just a little, but very weak sounding. Assuming the motor is shot.

Get ahold of Danny at Acculift, he will fix you right up and it's cheap compared to buying a new one. The seal on the end of the shaft over time needs to be reamed out as it gets too tight and drags on the motor, then you need a new motor.

Its not hydraulic, its a extending and retracting shaft powered by a Electric motor. I replaced the whole thing. I still dont know whats wrong. So if there is a relay the accuator will either work or not work at all if the relay is broken. Next thing I will try is shore power and see if its any different.

Have you checked your voltage to it?
It's just a dc motor.

My problem turned out to be a fallen pickup tube and a rotten grommet. The oil in the bottom of the tank had turned to grease as well. New fluid and grommet and its back to normal.

I am surprised that your problem is at the end of the stroke, I would assume that there is more load on the actuator when the hatch is horizontal then when it is at an angle.