40 HA basket case no upper controls

I picked up a 96? JLG 40HA not running has been sitting for years. the engine was seized up due to water in the exh. I replaced the engine and have been working through the bugs in the lift. all functions work from the lower controls. in the upper control everything works but the PQ controls. (all of them). drive and boom. with the help of the forums I have been able to get pretty far on my own. They have good voltage up to the basket through the foot pedal and to the controllers. going to them. I think I read somewhere about 3 relays in the lower box switching over from ground to basket controls. couldn't find anything on what switches them over. Is it a ground or a 12v that switches the relays? does it come from the basket or the switch in the lower controls? It is possible for all the PQ controllers to just be bad after sitting exposed to the weather for who knows how many years. I don't mind dropping the cash for all new ones. I just don't want to buy new if that's not the problem. I had to replace the circuit breaker, emergency stop switch, steering toggle and repair some wiring. also mice got into the control box and made a mess. thanks for any help

If you can't find a wiring diagram, POWER PROBE. If you can find a wiring diagram, POWER PROBE. If you don't know how to use one, youtube for an hour.

all the toggle switch controls in the basket work. steering, basket swivel boom in and out and basket level. It's just the PQ controllers that arent working.

I have a power probe and I do know how to use it. the wiring diagrams in the manual are garbage I posted on here because I have seen master techs that have years of experience on these lifts helping. I have years of experience fixing just about everything. this is my first lift and I really don't have any resources for troubleshooting and wiring diagrams. I didn't post on here to talk to people that have nothing intelligent to offer me.

Amazing, sparkymark1979, I have the same lift and literally the exact same story and problems. A 1993 JLG 40HA, not running when I bought it, cylinder head was damaged. Had to have the cylinder head welded and machined. Got the engine running and all functions work from ground controls, both on aux power and engine power. Upper controls, only the toggle switches work. The PQ switches cause the engine to come under hydraulic load but the functions don't work. I don't have any schematics, starting from scratch. I am not an experienced equipment mechanic but have done a lot of automotive work and I can follow a schematic and a path of logic. Like anyone else, I'm looking for guidance that might make my troubleshooting easier.

Oh, the steering toggle no longer works from my basket, but it does load the engine. It worked when I first got the lift running nearly two years ago. It's been sitting since and I finally got time this week to play with it.

Maybe I should have said "similar" problem because my controllers seem to be commanding something to happen, based on the audible engine load when they're activated. That might be different if your controllers are doing nothing.

ford guy I found my problem there is a solid red wire in the 16 wire harness it powers up the dump valve. like terminal 2 or 3. I guess its supposed to get power from the steer switch sounds like this could be your problem also. I had no voltage so I put power to it and started to get some function. I have a few bad PQ controllers. they work 1 way or when they want to. also I had green connections where the PQ controllers plug into the factory harness. I'm going to try a set of fisher plow terminal cleaners if they are the same size the look similar.

Thanks sparkymark. I didn't do anything with mine today, I was working on my Peterbilt... which always raises my wife's eyebrows, but that's another story. I'll try to dig into my lift in the next day or two. I previously pulled the connectors off of my PQ controllers and they looked pretty clean, no green fuzz. I do have some corrosion at the grounds in the upper control cabinet. The elements are probably our worst enemy. I know that my PQ controllers are at least causing some downstream action because I can hear the engine load, but it does act like the hydraulic circuit is closed. Man, a schematic would be nice.

fordguy I got my lift moving today. New PQ controllers. it was acting like the brakes were on. it wanted to move but wouldn't. tires would start to turn then stop engine was under load. did some testing brake solenoid had power when moving PQ controller took the valve out and it was opening and closing with power applied to it. figured the brakes were just stuck from sitting thought about disassembling them decided to try pulling it with my tractor with a helper trying to drive the lift. took a little but its all freed up and working properly now.

Thanks sparkymark. I still haven't gotten back to mine. Mine does roll freely. I can pull it around, and it will coast down a grade. Were you able to find a schematic?