Front lift issue

[Pietenpol]

70's, SS upgraded with expanders and sure-picks up front.


Had an issue where the front lift would only come on for one lane of the pair. I had more pressing issues so we used that lane last if necessary and turned it on manually up front. Got the chance to dig into it today and it no longer comes on from either pair. I exchanged all 3 relays with known good ones. It is getting 12 volts from the machines and all 3 relays energize when either machine is turned on. The lift will not run unless I turn it on by the override switch in the control box. Could this be caused by the thermal relay? That's the only thing I haven't swapped out yet. No spare but I can swap it over from the next pair. All the wiring looks good and the relay sockets seem fine.

[Will]

Do Sure-Piks have triacs in the control box like C-90, Options etc? That's normally the first thing I would change on one of them

[mechanic8230]

Have you changed out the Auxilliary switch yet? You might have lost a leg on the main and have to switch to Aux to make the return run. There also could be a couple of fuses mounted between the transformers in the control box that could have gone out.

[felix]

Sounds like a double chassis problem. Mp chassis has a M1 relay.(depress to make s-pik come on)
A&MC #3 & #3 short across?(should turn on)
Tray Lid making good contact?
Motor Plug shorting?