Elgin sweeper possible short to power

[Brandon3133]

Goodmorning everyone, I’m not sure if this belongs here but I have a Elgin crosswind J sweeper here that has what I believe to be a short to power somewhere in the circuit. I’ve been working on it the past couple weeks and haven’t had much progress. The problem is when I want to Turn on power for the left hand rotary brooms it does it’s job but also brings the right hand side brooms out, when I turn the switch to bring the right hand side brooms out it brings the left hand side brooms out and nothing else, when I turn on the power for the right hand side brooms it does it’s job fine, but the switch to bring the left hand side brooms out does nothing and is controlled by the right side. I believe it’s mainly a electrics issue so I didn’t really look at the pneumatics that much. I’ve checked the circuit breakers and they all look good, I’ve checked the relays too, two of them don’t get full continuity. If anyone has any ideas please let me know I’ll give it a shot.

 

[Delmer]

What does full continuity mean to you? How about ohms? across the coil and to ground both.

GROUNDS, GROUNDS, GROUNDS!!! You're going to want several test leads to be able to measure the voltage across the coil UNDER LOAD, that is, when it's acting up.

 

[Brandon3133]

What does full continuity mean to you? How about ohms? across the coil and to ground both.

GROUNDS, GROUNDS, GROUNDS!!! You're going to want several test leads to be able to measure the voltage across the coil UNDER LOAD, that is, when it's acting up.

I’m still pretty new to maintenance, full continuity to me means the lack of resistance along the wire, as of now I have the front wiring harness removed completely, I just found that there is continuity between a ground wire and an ignition wire as well as an auxiliary pump wire. I’ll start hooking everything back up and retest under load. Electrics is not my strong suit

 

[Brandon3133]

This picture is the ground with an ignition wire, It’s best to assume that this ground is somehow connecting to the ignition somewhere along the harness right?

 

[Delmer]

No, a short will blow a fuse usually. Don't assume, find a wiring diagram, check resistances and voltages. There's no way to figure this stuff out without a lot of testing and thinking. You have to understand resistance, load, volts, amps.

 

[Brandon3133]

No, a short will blow a fuse usually. Don't assume, find a wiring diagram, check resistances and voltages. There's no way to figure this stuff out without a lot of testing and thinking. You have to understand resistance, load, volts, amps.

I thought I had a good understanding, the only problem is that we don’t have the right schematics for this model, I’ve looked at the previous models to find similarities but there’s no progress on that front, I had to pretty much figure most of the stuff out myself, it was completely refurbished by the marine corps so I’ve been trying to get the new schematics, they’re really slow at responding to my request though. I also believe that there aren’t any fuses for the rear engine, there’s fuses for the front but the back I could only find the circuit breakers

 

[Delmer]

What's the history of the problems then? has this ever functioned correctly since the last guy had his mitts on it? (I don't care his certification or rank) Some things will change or break on their own, like wires cracking, connectors coming loose, corrosion, sticky valves. Some things won't change on their own, wires won't switch around, pneumatic tubing won't change solenoids. so it helps to know the history.

I would guess a short to ground would blow a fuse, trip a breaker or melt something (like the whole dang sweeper). If there was another load on that ignition wire between where you're measuring, that would look like a short to a sensitive continuity tester. I think you're going to have to figure out a little of the wiring yourself, the solenoid wiring is probably all similar so you figure out one, you've figured out them all. I'd concentrate on the ground side. Then measure the actual voltages (across the solenoid, not from the hot side to a different ground) when it's malfunctioning, that will tell you where the voltage is and where it isn't, not where you guess it is going based on your other tests.

 

[Brandon3133]

I did all you sa

What's the history of the problems then? has this ever functioned correctly since the last guy had his mitts on it? (I don't care his certification or rank) Some things will change or break on their own, like wires cracking, connectors coming loose, corrosion, sticky valves. Some things won't change on their own, wires won't switch around, pneumatic tubing won't change solenoids. so it helps to know the history.

I would guess a short to ground would blow a fuse, trip a breaker or melt something (like the whole dang sweeper). If there was another load on that ignition wire between where you're measuring, that would look like a short to a sensitive continuity tester. I think you're going to have to figure out a little of the wiring yourself, the solenoid wiring is probably all similar so you figure out one, you've figured out them all. I'd concentrate on the ground side. Then measure the actual voltages (across the solenoid, not from the hot side to a different ground) when it's malfunctioning, that will tell you where the voltage is and where it isn't, not where you guess it is going based on your other tests.

i did all you said and figured out the problem. It was the solenoids, checked everything and plugged them back in according to our outdated schematic and it worked. I appreciate it, haven’t been a mechanic long so this forum has been really helpful!

 

[Delmer]

So a loose connection at a solenoid? or your replaced a solenoid? or maybe just wiggled a wire that will wiggle itself loose again?