Dump hydraulics stopped working

Hi All. I have an '89 Ford FSD with a Dyna Jack M-3551 electric/hydraulic hoist. Recently, while under load, the houst stopped working. It's a power up/down system and right now all it does is click when I press either the up or down button on the remote. It is stuck at about 8" lifted. I charged both batteries fully thinking I had inadequate power but it made no difference.

Anyone have any ideas. First the up dropped out, so I went to lower it and it went about 2 inches down before the down dropped out.

Thanks in advance for your help.

Your electric solenoid is stuck/bad. So it is not opening or closing when it should. Charging the battery would have little effect.

Thanks JD Seller. Sounds like I should replace. What about a weak ground? I read that would create a problem with the solenoid. Though I don't know why it would suddenly become weak but it is an 89 so...

Welcome shovelhead!

Sounds like a loose connection, a bad solenoid, or a problem with the motor. Look for the obvious first, loose connections, broken wire, connections that appear to have been hot...

You'll need a test light or volt meter. Since it it power up and power down, the motor should run and one solenoid should get power whenever it is activated.

The motor will look and act similar to a starter motor. If the click you hear is the solenoid on top of the motor, hold the up or down button, check for battery voltage or a bright test light on the main lug going into the motor. Check between the lug and the motor case. If you have power there, and the motor is not running, there is a problem with the motor, or if the motor and cables are getting hot, possibly the pump is locked up.

If there is no power to the motor, and the solenoid is energized, and there is power on the battery cable, the solenoid contacts are bad.

If you find a problem, chances are a starter/alternator shop can repair the motor or supply parts.

But whatever you do, be EXTREMELY CAREFUL working or reaching under there! Anything is possible with a malfunctioning lift. Don't give it a chance to get you!

I would check the wiring out as it could easily be a broken/bad wire that is making the solenoid not work. Spent the time to find the problem do not just replace parts.

First make sure everything is getting power. Sounds like a bad conection somewhere to me. Could be a motor or solenoid problem too, but you need to start diagnosing from the beginning and work along the path of power til you come to the problem. So start with checking the batteries to make sure you dont have a bad one. Then check all the wiring and switches. If its not there, then move on to the solenoid and motor. If you bounce around you could miss a small problem and fix things not broken.

I know it may seem to be obvious but block that bed if it is up in the air! IF something should start to work you may not want it to make unexpected moves if you are under there.
Andy

Thanks Andy. I blocked it with some 6x6 stock right away. It's fully loaded. Didn't want that weight just sitting up there.

Thanks everyone for taking the time to read and reply. I planned on testing all my connections this weekend when I find a few or 8 hours. My hope in posting here was 1) I'd get confirmation from the forum that it sounded most like a poor elec connection and 2) Someone else may have experienced a similar problem and found it to be poor connections.

A brief inspection of the connections looks suspicious. There's a ground cable from the battery to the frame with a fair amount of obvious corrosion. I'm sure I'll find more of the same as I explore. Regrettably the bed is limiting my access to the pump because it is nearly down. Wishing I were a skinnier man.

This is why I recommend that the pumps always be out where you can get at them. Just a week or so back someone posted about moving his pump or battery under the bed. That is always a bad idea. Good luck on your repair.

ive got a similar older system which i just went thru on my truck, if you just get a good solid click you have an electrical issue, first make sure your batteries are good with no dead cells, if there good, [ a cheap way to test is see if they will start the truck] then check all the wires, especially the ground, they need to be clean, with bright bare and tight connections, if all that is good, then 90% chance the solenoid is bad, now some of these look like the ones that used to come on the fenders of ford trucks and cars 30 years ago, they are not the same!, its critical to tell the parts man they you need one designed for continuous duty, tell him what it goes on, if he's young and lost, have him get out his standard ignition parts book, in the picture section where all the solenoids are, you will find descriptions of each by the picture, you can find one rated for continuous duty there a regular one like for fords will burn up in only a few cycles, its possible the electric motor is at fault but its only possible its very unlikely

I would say either the solenoid or a bad connection.

A lot of great help on this board. Many thanks!

Found a suspect. Ground from dump battery was garbage.

Replaced all the cable ends, created a new bare metal ground to frame, and then put up 6100 pounds without breaking a sweat. Amazing what solid connections can do. It dumps better than it ever did before. Thanks to all for the good advice.