First-time post!

The mast tilt and side-shift pump on my elderly ERP035 stopped working last week, and I'm hoping to diagnose (and fix?) the issue before shelling out for a spendy on-site tech visit.

This old lift has exhibited erratic behaviors for a while. Occasionally the none of the drive or hydraulic functions respond, but usually return once I turn the key on and off. Battery voltage is good, and holds up relatively well. I had a forward/reverse switch failure last year that I first thought was in the switch itself, but was resolved (after a new switch didn't fix the problem) by replacing the traction control module. When I first acquired the lift, I believe the main lift pump only ran when I was actively raising or lowering the forks, but shortly after I got it the main pump started running continuously unless I'm out of the seat.

Starting last week, the mast tilt and side-shift pump stopped operating. The control solenoids do engage when I manipulate the controls, but the pump (separate from the main lift pump) does not energize. I opened the compartment housing the solenoids under the RH flooboard, sprayed them thoroughly with contact cleaner, and gave them a quick buff with emery paper, but the pump still doesn't come on. The fuses associated with the tilt solenoids appear intact (but I haven't confirmed with a VOM).

I don't have a way to check codes, but can trace circuits with some guidance. The only maintenance/repair manual I have is for a later model ERP030-040 TFN, dated 1997. My lift is definitely older.

What would be my next diagnostic steps given minimal specialized equipment? My gut says the fault is electrical, not hydro-mechanical. Before I start searching for a used tilt pump control card, what should I be checking? Are there any simple cut-outs, breakers or fuses I should be examining? I'm not sure that the circuit diagram in the repair manual I'm referencing is that relevant for this older machine. But it's my one-and-only, and I can't operate without it (nor can I afford a more reliable replacement).

Thanks in advance for the wisdom of the crowd!