need help with electric dump bed please

[mikeandmary]

So busiest day of the year yet for my business tomorrow, and the dumpbed on my delivery truck quit working. I would sure appreciate some help figuring this out. the hoist is controlled electronically and it went completely dead this afternoon. did some poking around, fuses are good, have continuity everywhere on the wiring, etc. switch does nothing. it has a 3 post solenoid on it, 2 large (red/black) and a 3rd smaller post. i can jump the red/black and it runs, or the small post and positive and it runs, but in both cases it's trying to go down. i'm assuming the solenoid is bad? problem is some idiot mounted the thing under the bed, inside the frame rails, so it's all i can do to see the thing, much less touch it.

anyone have any idea how to make the thing run up instead, so i can at least get to it?

Does my assumption sound correct on the solenoid?

sure would appreciate some quick input as i stare blankly at it wondering what to do next. thanks.

[Nashotah7]

Yes you have a bad solenoid. If you can, skip the solenoid and jump directly to the motor. When you do get it up, make sure you prop it up with the attached prop supports or with a piece of metal from the underside to the ground. That is why I stopped running electric lifts on the small trucks years ago, some of the most undependable crap around. Good luck.

[mikeandmary]

awesome, thanks for the quick reply. now if i could just figure out how to get it to run the opposite way so i can raise it up enough to get the solenoid off. any ideas?

[mikeandmary]

after many frustrating hours of messing with this thing, we swapped out the solenoid, no change. ended up taking it to a dump dealer, and they quickly found a the remote wire had been pinched and cut by the seat slide. the original solenoid was good. They spliced it back and got me on my way. On getting to my first delivery, i raised it up and noticed immediately that it's running slower and lower pitch than before. while raising, it twice suddenly jumped to full power for a second, then back. Bad connection somewhere i thought, i'll check for a loose connection when i get back. Got it all the way up, let go of the button, and it keeps on running. panicked, i start pushing the up/down buttons trying to get it to stop. starts going down finally, and wont stop either. finally it quit, but has continued to have both problems on subsequent deliveries. At the risk of burning up the motor, i had to keep going. After tooling around with it back at the shop, the battery lead to the solenoid and the solenoid itself are quite hot, even saw a waft of smoke from the + terminal, after usage. No obvious looseness anywhere, i need to check it with a voltmeter, i guess, and that makes sense with the low power, but that wouldn't cause the constant running issue would it? i'm thinking thats got to be a switch wiring problem? any ideas?

[Nashotah7]

Try this site, plowsite.com.

[RedBKM]

It sounds to me like you're still having remote problems or a sticking pump solenoid. The changing pump speed may be a loose power or ground connection. If you have access you can test it out with a set of jumper cables and a battery.

My F450 has a power up/gravity down and I've replaced the flow solonoid twice in 5 years. This is the one that releases the fluid into the tank and lets the bed go down. In both cases it failed in the UP position! To get it down I had to loosen the valve and let it leak into a bucket. If you ever need to replace one be sure to get the new design with a manual backup.

[mikeandmary]

Just recently we figured out that it was the solenoid. It took us 3 of them and several visits to the mechanic to figure it out. I've gotten bad parts before, but getting two in a row is a new one. that's frustrating, wasted a lot of time checking eveything else again and again.