# 2 Plug Fisher MM1 - Clicking at pump - blade does not move



## 86turismo (Oct 31, 2014)

HI All,
This is my first plow, and I am in desperate need of some help!!

What I have:
* 98 Chevy K1500 Ext cab 5.7L
* Older Fisher MM1 2 Plug system with the headlight relays

I After many days of researching to find wiring schematics I wired up the plow last night.

Below is the wiring schematic I found.

The light on the joystick/controller lights up. For now I just have the hot wire for the controller plugged in to fuse 17 in the fuse panel on the left hand side of the dash by the driver's door.

The motor relay has one side labeled at BAT. assuming that means battery side.

When I first wired everything up I did not realize I had the ground wires crossed. I had the Brown/Red wire on the side labeled battery and the Orange/Black wire and the Black/Red wire on the other side. When I plugged in the harness to the plow I could hear the motor running and the power wires were getting hot. So I unplugged the harness. I only had it plugged in for about 10 seconds as I was pretty sure the pump should not be running until I used the controller.

I then switched the ground wires around at the motor relay. The pump did not run as it did before. I moved the stick around on the controller, but the only thing I get is a "click" when I move the stick to the up, left or right positions on the controller.

Do you guys have any thoughts as to where I start to trouble-shoot? Did I burn out the motor relay when I had the ground wires reversed? Is there a way to go directly from the battery to the pump motor to see if it's working OK?

If I were to pull the pump motor and take it to a Fisher dealer could they test it for me?

Thanks guys for looking and for your advice.


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## kimber750 (Sep 19, 2011)

86turismo;1865829 said:


> HI All,
> This is my first plow, and I am in desperate need of some help!!
> 
> What I have:
> ...


Quickest test you can do is put screwdriver across the two large terminals on solenoid/relay. Or you can use jumper cables from battery to plow motor. Just stay clear of the plow. Make sure connections are clean and tight.


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## 86turismo (Oct 31, 2014)

When you say solenoid/relay are referring the part I referred to as the motor relay?

If I go the jumper cable route to bypass the motor relay will the plow move up/left/right once I make the connection? If the answer to that question is yes and the plow raises up with it drop hard when I disconnect the jumper cables?


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## kimber750 (Sep 19, 2011)

86turismo;1865879 said:


> When you say solenoid/relay are referring the part I referred to as the motor relay?
> 
> *YES*
> 
> If I go the jumper cable route to bypass the motor relay will the plow move up/left/right once I make the connection? If the answer to that question is yes and the plow raises up with it drop hard when I disconnect the jumper cables?


Plow shouldn't move at all with out valves energized but it may depending on what relief is weakest. You can remove the lift chain to keep it from raising but it should not come down on it's own unless something is wrong with pump.


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## 86turismo (Oct 31, 2014)

Here's an update.

I took a pair of jumper cables from the battery directly to the pump motor. I can lift, lower, angle left/right as expected using the joystick.

So I have limited the trouble to the truck side power cable, plow side power cable, the connections in the plugs or the motor relay solenoid. 

I see on Tractor Supply and Advanced Auto that they have "car starter motor solenoids" I am wondering if there is anything special about the one that came with the wiring for the truck/plow or if any "car starter motor solenoid" will work.

What is the best way to see if I have 12v at the pump motor using the wiring for the truck and plow? I am assuming I would need to hook up all of the wiring and then have someone move the joystick while I test across the terminals on the pump motor.

Any thoughts...?


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## kimber750 (Sep 19, 2011)

86turismo;1866234 said:


> Here's an update.
> 
> I took a pair of jumper cables from the battery directly to the pump motor. I can lift, lower, angle left/right as expected using the joystick.
> 
> ...


Buy a plow solenoid, car starter solenoids are not designed for plow use.


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## dieselss (Jan 3, 2008)

Yes, hook it up, and text light the output while operating the plow functions. You do have the solenoid hooked up properly correct? Batt in, batt out to plow.....big terminals
Ground, small terminal
Signal power from clicker to other small terminal


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## 86turismo (Oct 31, 2014)

dieselss,
I do have the big wires going to the battery and plow (Red/BLK). I have the black cable going directly to ground on the battery.

Another question I have. Are *ALL *4 post motor relays (solenoids) configured the same in that the Battery Side and (S) terminal are always on the same side of the solenoid and the power output (say to the plow pump) and the (I) terminal always on the same side?


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## 86turismo (Oct 31, 2014)

Hey All,
Just wanted to say thanks to all of you for your input and encouragement. I have the plow fully up and running.

The issue was I did not have the solenoid grounded. All this time I just had the wires sitting on top of the truck and dangling where ever.

Thanks again and happy plowing!!

Scott


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