LXI slide not extending

[Pjanecke]

Retract works fine.
When extend is pressed, the operational ground at the switch panel is lost, EG Amber ready light immediately goes out and the pump doesn’t come on. On the relay board both the yellow and red unlock leds are on when the extend is pressed. Lock and room in LEDs all show green.

As part of testing, I’ve jumped power to the unlock and extend hydraulic valves and they both work.

A week ago I called HWH tech support and am still awaiting a call from a tech.

Any ideas on what to check next appreciated!

Thanks
Peter Janecke
2001 LXI (new to me)