But wait; more box truck saga

[Toolmaker51]

"I'd appreciate assistance selecting components to build a latching relay for 1) to not make it a two handed affair. Electricity I can reasonably kluge. Electronics is not my forte'. Found all kinds of info on the DIY process but little [none] about 12 volts running equivalent of a Delco starter motor, there is some amperage, especially to tap the 3500 pound capacity. The truck wiring has a thermo breaker for overload/ short circuit conditions."

A little more information would be helpful. So I'll take a stab at it anyway, first off you mention#1 energizes the circuit it this merely an on off switch that allows electrical supply to the control pendant? Will make the assumption that is the intention. and if so then I would speculate that the rest of the switches are dpdt momentary contact. each one energizing their respective hydraulic function while energizing the motor relay, atleast that is how I generally wire up my multiple hydraulic functions. If you are doing it another way please advise.
Note you know how to make this a 2 way conversation

"Note you know how to make this a 2 way conversation" That is a big issue in education; only good teachers encourage that, and our Frank S is one of the best.

I'm relearning the lingo, but can describe well enough
Correct; 4 identical momentary switches, all SPST (On) Off. Amid disappointment that design isn't offered SPST Off-On to place in *4, justifying the latching relay instead. Not unlike an E-Stop, just not so obvious an invitation for pinheads to mess around with.

Lift-gate is a Waltco made in 1995, with 1 main pump and a standby. I'd bet anything main pump is same motor as a Delco starter.
The replacement loom has four leads for operation switches, for that year of manufacture, today's are different. Had to get help from a local liftgate mechanic, my process of elimination wasn't working, didn't realize second motor was a standby. Condition of the old loom wasn't much help either. Anyway, I had the loom in right, he joined the terminals of 4* and presto. Greased some fittings, took some measurements, he had the rest going in short order.

The latest switches are in exactly as he did, WITH intention of making 4* operative as a safety lock-out, forcing deliberate usage, just 100% upgrade in weather resistance. I tested briefly, it works as expected, but full test wants to warm up engine and fast idle to maintain battery power, the gate isn't self powered electrically.

Haven't done anything that would alter from running right; old switches were sticking in ON position and gate would descend (gravity+ open solenoid) by itself, unless finger was removed from switch smartly, just letting go wouldn't. UP did same, tending to push limit switch, another undesirable action. Don't know what that platform weighs, it's considerable. Not something I want running amok.

What I've learned unexpectedly, isn't just saving receipts, but labels or containers parts come in. Makes me a little smarter describing specifics, and I'm doing a note page of steps taken.
Even baby steps.

[Frank S]

"Note you know how to make this a 2 way conversation" That is a big issue in education; only good teachers encourage that, and our Frank S is one of the best.

I'm relearning the lingo, but can describe well enough
Correct; 4 identical momentary switches, all SPST (On) Off. Amid disappointment that design isn't offered SPST Off-On to place in *4, justifying the latching relay instead. Not unlike an E-Stop, just not so obvious an invitation for pinheads to mess around with.

Lift-gate is a Waltco made in 1995, with 1 main pump and a standby. I'd bet anything main pump is same motor as a Delco starter.
The replacement loom has four leads for operation switches, for that year of manufacture, today's are different. Had to get help from a local liftgate mechanic, my process of elimination wasn't working, didn't realize second motor was a standby. Condition of the old loom wasn't much help either. Anyway, I had the loom in right, he joined the terminals of 4* and presto. Greased some fittings, took some measurements, he had the rest going in short order.

The latest switches are in exactly as he did, WITH intention of making 4* operative as a safety lock-out, forcing deliberate usage, just 100% upgrade in weather resistance. I tested briefly, it works as expected, but full test wants to warm up engine and fast idle to maintain battery power, the gate isn't self powered electrically.

Haven't done anything that would alter from running right; old switches were sticking in ON position and gate would descend (gravity+ open solenoid) by itself, unless finger was removed from switch smartly, just letting go wouldn't. UP did same, tending to push limit switch, another undesirable action. Don't know what that platform weighs, it's considerable. Not something I want running amok.

What I've learned unexpectedly, isn't just saving receipts, but labels or containers parts come in. Makes me a little smarter describing specifics, and I'm doing a note page of steps taken.
Even baby steps.

Do you happen to know which series liftgate you have IE (C) (EM) (EM/TC) (HLF) or (WFL) these are the Waltco flip away style liftgates
When folded away does it rest in a cradle or does it have a mechanical safety latch to prevent it lowering accidentally. If it has neither let me know and I'll give you some pointers on how to construct one that can the released by a solenoid

[Toolmaker51]

Do you happen to know which series liftgate you have IE (C) (EM) (EM/TC) (HLF) or (WFL) these are the Waltco flip away style liftgates
When folded away does it rest in a cradle or does it have a mechanical safety latch to prevent it lowering accidentally. If it has neither let me know and I'll give you some pointers on how to construct one that can the released by a solenoid

This part, no kidding, I have memorized.......
It's fold away, retained by automatic and manually set latches, not cradled.
Model 323
Serial 323344
Capacity 3500
Date 5-95
That makes it a WDL-35 RM with 102" width (box width)