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Discussion Starter · #1 ·
My E47 was intermittently working but would sometimes go left when trying to swing right and also swing left when trying to raise. After about 30 minutes of this the plow would only go left and not raise, so I dragged it into the shop and started diagnosing. 2 valves are new, new fluid. I started checking voltage check with a light style tester with wire to ground. I started with switches and found voltage everywhere, as if everything was energized. Went to the plow and with the key off I had voltage at all the coils, the base of the pump, the pump motor body and even the chassis of the truck; all were hot. I disconnected the hot lead coming from the relay to the pump motor and everything deenergized, so naturally I figured the motor was worn and finally shorted out. I checked continuity from the positive post on the motor to it's case and indeed there was continuity.

I just received a, supposedly , new motor and right out of the box checked the continuity from the positive post to the casing and there is continuity. I know the motor grounds through the case when bolted on but should I have this connection from positive connection to the casing? Seems like its a direct short to me? Defective motor?

I
 

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Discussion Starter · #2 ·
Correction to the original post: the truck key was on. It was also possible the ground cable was off and the voltage was "searching" for a ground but it still seems the new motor has a direct short. Anyone know what the resistance from the positive ground post to the motor case should be?
 

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Get a set of jumper cables
Use the +pos, hook it to the +pos on the batt
Then to the stub on the pump motor.
does it run?

no
Hook up the -neg to the batt and to the case on the pump motor, if it runs now , =bad ground
 

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Discussion Starter · #5 ·
My ground cable was off when I was doing the voltage check on the truck. Ha-That would definitely cause a bad ground. It's a habit of mine to disconnect the ground at the battery to avert any drains and I forgot I had done it. I was just dumbfounded to see voltage everywhere. I took off all the connections anyway and cleaned them all up. Always a good practice with these plows. I installed the new starter which drew less amperage. The old starter, built in 1988, would sometimes kill the truck. Also, I did a ohms test on each winding of the old motor and the readings were all over the place : 2 to 400 ohms. The new motor had a consistent 2.4 ohms all the way around it, so I justified my purchase to make me feel good!

The original problem was an intermittent malfunction of both trying to raise the plow and trying to turn the plow right. Sometimes work, sometimes go left on both. It was going into the default mode to go left so I traced it back to the raise/ lower switch and found it wasn't working consistently. I took it off, took it apart and cleaned a small amount of carbon of the terminals and it's now working with a meter. I'm anxious to get it back on the truck later today to try it. Thanks for your input. I'll keep you informed. I should know in short order.
 

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Discussion Starter · #6 ·
Well, I put the switch back on the control panel and thought I'd better check the left/right switch before I mounted everything back under the dash. There was no output from the right side wire. Who'd of thought? I disassembled that switch, cleaned the carbon of the terminal, which were hardly worn or dirty and put it back together. I got everything mounted and fired it up and it runs like new. I would have never believed two switches were giving me intermittent problems at once. So anyway, thanks dieseldude and SnoFarmer for your input. The good thing is it's running well.....today.
 
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