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Discussion Starter · #1 ·
I apologize for the novel that's coming....

We have an 8' Unimount on a 1998 Chevy K2500. We bought the truck with the plow about 7ish years ago. The plow worked great, until last year.

One of the guys who was driving it told us that it would not move up/left/right. He said he could get it to work for about 10ish minutes by (slowly) pushing it against a curb or a pole while operating the controls. He did that the rest of the night. Got the truck/plow back to the shop, and started troubleshooting. As usual, the plow worked fine at the shop. We changed the fluid, filter, and removed the pump. I took the pump apart, inspected/cleaned it, and reinstalled it. Everything worked fine in the shop. The next time out, it did the same thing after he had been using it for a 3-4 hours. I talked to a friend of mine, who told me it might be a wise idea to change both poppet check valve assemblies, as well as the crossover relief valve assembly. At the same time, I also changed the motor just as a precaution. Next (and last, for the season) snow, the same thing happened. All valves/coils were removed, cleaned, and bench tested with no issues

This season rolls around, and we have a new guy out plowing with it. I'm in a parking lot with him, and the plow does the same thing. I go up to the motor and touch it, and it's pretty warm considering it was only 5 degrees F outside. So, I told him to wait 10ish minutes, and try it again. He did, and the plow worked for a few more hours. We get the truck back that night, and I decided to change the motor (that only had maybe 8 hours of use on it) and the solenoid, because I thought maybe the almost-new motor may have been defective.

Fast forward to January 28th-29th snow, and the same thing happens. He texts me and tells me that the plow is doing the same thing (I can't remember if the motor makes noise or if just the solenoid clicks. I'm about 99% sure that the motor does energize and sounds like it wants to work). He said he packed some snow around it because it was warm, waited 5-10 minutes until it was working, and then he went on his way. That snow was also about 0-5 degrees F.

Last year, I thought about just saying F it, and buying a whole valve body (already assembled). However, this year, I'm almost tempted to buy a new positive/negative cable on the truck and plow side, and then making a new positive cable for the solenoid to the battery just to see if that does anything. I know that old/corroded/dirty cables that aren't making a good connection usually generate heat. I'm wondering if there is something going on with these cables (from motor-solenoid) that we can't see.

Out of 8 plow trucks (5 total unimounts), this is our only problem child. The truck runs great. It's a shame that whoever is in this truck gets frustrated because the plow has intermittent problems that I can't figure out. If anybody has any ideas on what to do with this thing, it would greatly be appreciated.
 

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Discussion Starter · #3 ·
This truck has two new batteries as of this year, with all 1/0 wiring (and big 6 done). Every time it's happened, before we do ANYTHING on any plow that is not operating, we ALWAYS wiggle the positive/negative plugs while somebody is operating the controls, as well as check the battery and solenoid connections. I'm almost positive that the motor runs when this issue happens, but the plow doesn't move.

I guess I just don't know if the motor getting warm plays a part in this. It seems as if letting it cool down will make it run again. I would almost chock this up as the operator is "playing" with the controls too much, but I did speak with him about only moving the plow position when he has to. I've had some operators in the past that just feel like they always have to be messing with the controller. This guy (responsible and has common sense) has assured me that he is only moving it when he has to.
 

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Are you sure that the plow wont raise either when it's doing this? If so, when he tries to raise, does it do anything?

The fact that he can push it and get it working makes it sound like one of the angle rams is getting bound up, but that wouldn't affect lifting
 

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What pressure are you reading at the pump?

After you Disassembled the pump, confirming pressure after reassembly, is my first step

Working fine in the shop, then not working properly 3 to 4 hours later seems to be weather, or electric connection related.
 

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Discussion Starter · #7 ·
what are you using for oil?
We're using Angelo's plow fluid. We've been using it for at least 10 years now and have never had fluid related issues due to this fluid (not saying it's not possible, btw).

Are you sure that the plow wont raise either when it's doing this? If so, when he tries to raise, does it do anything?

The fact that he can push it and get it working makes it sound like one of the angle rams is getting bound up, but that wouldn't affect lifting
The plow will only lower when this happens. No left, right, or up. I also had him try to tap on the motor lightly with a hammer while his passenger is working the controls, to no avail.

What pressure are you reading at the pump?

After you Disassembled the pump, confirming pressure after reassembly, is my first step

Working fine in the shop, then not working properly 3 to 4 hours later seems to be weather, or electric connection related.
I have not tested pressure yet. I need to get a gauge and the fittings for the RT3 and the Westerns though. I'm just lazy and haven't pieced together all of the fittings/gauge that I want/need. The plow operates at normal speed when it is working. When this issue was happening last year, it wasn't this cold. I'd say it was probably as warm as 30 degrees F last year when this was happening.
 

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Have you tried this plow on a different truck yet?

Confirming whether or not the motor is running when its having the issue is critical. That will tell you if its hydraulic/mechanical or electrical and rule out half your options

Its unlikely, but how old is the solenoid? It is possible the solenoid is overheating and not engaging. Again, whether the motor was running or not would help rule that out.
 

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Discussion Starter · #12 ·
You guys are hilarious! Haha

The solenoid was new before this plow, along with the plow motor. We only use the Western solenoids on all of the trucks, we got away from the cheapies a few years back.

I like the idea of trying the plow on a different truck. I will do that for the next storm and see if it changes with the vehicle. Again, I wasn't sure if the increased "feel" of the temperature on the motor had anything to do with it, I just feel like when the windchill is that cold, it should, at most, be luke warm to the touch. It wasn't HOT, but it definitely felt a lot warmer than it should have been.
 

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When its acting up, with out trying to fix it, how long will it stay "broke"?

What's the possibility of keeping a test light or meter with the truck to try and start diagnosing it? And remember when checking the power at the motor, do not use the power at the motor, go straight to battery with the test light clip.

I would try to put this plow on a different truck and see if follows the truck
 

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Like previously stated. Best to try on different truck to help rule out certain things!
 

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Discussion Starter · #15 · (Edited)
When its acting up, with out trying to fix it, how long will it stay "broke"?

What's the possibility of keeping a test light or meter with the truck to try and start diagnosing it? And remember when checking the power at the motor, do not use the power at the motor, go straight to battery with the test light clip.

I would try to put this plow on a different truck and see if follows the truck
It usually will stay "broke" for anywhere from 5-15 minutes, and then work for another few hours, give or take.

When you're talking about diagnosing with the test light, what exactly do you mean? If the motor is making noise, that means it's getting 12v+, right? I'm thinking maybe taking a DMM with me and seeing if it's actually receiving 12+V. Also, I could take an amp clamp to see what kind of current draw it's pulling. I know bad motors will draw excessive current and REALLY tax the electrical system, but maybe it's not pulling enough amps to move the plow because the motor is so hot? If so, couldn't bad +/- cables from battery/solenoid to the plow cause that? I'm thinking it's not the motor, since the old one (that was only a few snows old), as well as the new one, that is now only one snow old.

I'm thinking I will definitely put it on a different truck. I'm also thinking of giving up the throne on my truck to hop in that one, to see if maybe it IS operator error. I think I'll trade plows first though. That seems like the easiest and most comfortable choice for me, first. :laugh:
 

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When you're talking about diagnosing with the test light, what exactly do you mean? If the motor is making noise, that means it's getting 12v+, right? I'm thinking maybe taking a DMM with me and seeing if it's actually receiving 12+V. Also, I could take an amp clamp to see what kind of current draw it's pulling. I know bad motors will draw excessive current and REALLY tax the electrical system, but maybe it's not pulling enough amps to move the plow because the motor is so hot?
If it is definitely making noise, then the test light isn't needed. But in your earlier post, you said your guys weren't positive it was, and in fact you mentioned them rapping on the motor to try and fix it. If it was already spinning and making noise, rapping on it wouldn't do anything.
 

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Workie, no workie, workie, no workie...

Either bad connections somewhere, or the driver is sleeping in a running truck, in a parking lot behind the 7-11, and "saying" it aint working..

Test light, continuity tester, multimeter, wire brush, dielectric grease, a couple hours of cleaning / fiddling / checking, and who knows ? maybe it will workie, workie, workie.
 

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Discussion Starter · #18 ·
When its acting up, with out trying to fix it, how long will it stay "broke"?

What's the possibility of keeping a test light or meter with the truck to try and start diagnosing it? And remember when checking the power at the motor, do not use the power at the motor, go straight to battery with the test light clip.

I would try to put this plow on a different truck and see if follows the truck
If it is definitely making noise, then the test light isn't needed. But in your earlier post, you said your guys weren't positive it was, and in fact you mentioned them rapping on the motor to try and fix it. If it was already spinning and making noise, rapping on it wouldn't do anything.
I couldn't remember at first, but I am almost positive that the motor was making noise like it wanted to move. I did tap on it before just for sh*ts, as it worked on our ultra-mount when that motor was pooping out. It would make noise, but the plow wouldn't move unless I tapped on the motor.

Workie, no workie, workie, no workie...

Either bad connections somewhere, or the driver is sleeping in a running truck, in a parking lot behind the 7-11, and "saying" it aint working..

Test light, continuity tester, multimeter, wire brush, dielectric grease, a couple hours of cleaning / fiddling / checking, and who knows ? maybe it will workie, workie, workie.
When it happened two snows ago, I was in the parking lot with him. I noticed he wasn't moving, so I went over and he said the plow wasn't moving. That's when I felt the motor and noticed it was warm. It was making noise, but the plow wasn't moving. I think you're on to something with the cleaning/checking TLC. After I spend some time on that, I'm still going to switch the plow with a different truck. I should just buy the new power/ground cables from plow-truck, since those have been on the truck/plow for as long as I've owned it. If that doesn't fix it, I'll probably go the new valvebody route. If THAT doesn't solve it, I'll drive the truck and plow to the scrap yard that's a few blocks over and be done with it. I HATE problem trucks!
 

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I

When it happened two snows ago, I was in the parking lot with him. I noticed he wasn't moving, so I went over and he said the plow wasn't moving. That's when I felt the motor and noticed it was warm. It was making noise, but the plow wasn't moving. I think you're on to something with the cleaning/checking TLC. After I spend some time on that, I'm still going to switch the plow with a different truck. I should just buy the new power/ground cables from plow-truck, since those have been on the truck/plow for as long as I've owned it. If that doesn't fix it, I'll probably go the new valvebody route. If THAT doesn't solve it, I'll drive the truck and plow to the scrap yard that's a few blocks over and be done with it. I HATE problem trucks!
Before you do,that, post your location, and offer the plow for sale to someone here willing to spend,time on it.
 

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Discussion Starter · #20 ·
Ok, just an update...

Last night, I figured I'd do some inspecting/cleaning on the plow since I had to fix a shorted parking light wire.

The plow draws about 193ish amps, which is normal according to the manual (max 200 amp draw). The plow side +/- connector is brand new, and the truck side looks maybe a few years old. The ring terminals are still shiny. Regardless, I cleaned both male and female ends of the plugs with the connector cleaning tools that I have. I got a lot of nasty dirty gunk/grease out of the female end. I sprayed it out with brake cleaner, and put dielectric grease on it. The positive cable from solenoid to battery is also new-ish with shiny lugs. I'm still going to swap the plow with a different truck for the next snow, and see how that goes. I'm hoping it follows the driver, just to put my mind at rest and so I can teach him to help him try to avoid this.
 
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