Dover solid state issues

I have a Dover solid state with the power, door, car, top & bottom, and intermediate floor cards..issue at hand is that the car is yo yoing so to speak..place car call to 3 it will go to 4 cycle the doors go down to 2 and cycle the doors..then continue to run back and to those floors and never answer 3rd floor car call..I have replaced all cards, added resistor to pc-24d to rid the ac ripple, cleaned all relay contacts etc checked grounds so forth..any insight??

I bet you its one of the two third floor limit switches mounted to the duct. I'd Park it near them switches, LOTO it, and clean the contacts with emery cloth, hit it with contact cleaner to get rid of grit and check the contacts are making. I had a three stop doing the exact same thing, it was those switches.

I was in the process of cleaning and checking the switches when you responded, its been back in service since with no issuses..should've noticed it when floor 3 didn't show up on the car PI when I was running it..thanks for the insight though!