Have a 5 stop duplex with one car randomly shutting down.Find car PI flashing an out of group different floors.Trudge across snow filled roof,open controller door car takes off also,left door open couple days later same problem open swing panel car takes off left both doors open an ck for loose wires change soom relays but happened again tonight going there first thing in morning any suggestions would be great.

I have over the years had broken grounds on relays on the backplane.if safety circuit is intact..and doors are good (DR) may be a MGS.circuit problem..hook circuit is controlled by floor landing relays..make sure you do not have a out of step problem.will cause all kinds of shutdowns at various floors..best thing to do with this stuff replace as many of the cube relays you can.once you fix the problem..good hunting..

Sounds to me if you have either a coil that is on the way out and your movement vibration ticks it over enough to come in or a dicky earth on the cabinet when you touch it(body resistance) however unlikely. Run the lift and check all relay armatures to check action is snappy and check terminal connections to start with.