Plow wiring problem ?


Senior Member
I Just switched my uni-mount plow over to another truck & I can't get the plow itself to work.

I have all the lights working which I thought would be the hard part since I had to install a DRL kit.
But when you go to use the plow all it does is click the solenoid, no power goes through to the pump.

I cleaned all the connections everywhere and it still does the same thing.

I thought it was a bad solenoid but the new one does the same thing.
I thought it might be a bad ground to the solenoid so I ran a separate wire to the solenoid from the battery.

On the western solenoid there's 2 wires on the solenoid.(besides the battery in & out to the pump)I have power when you move the joystick for the plow in the wire to activate the solenoid but it still won't work.
Is the other wire supposed to be a ground? And if it is can I just ground it to the battery or do I have to ground it some other way, such as back through the plow harness?

I tried grounding that terminal on the old solenoid & it worked so I hope thats all it is.

thanks for any help,
I tried the old solenoid and if I ground that wire terminal and apply power to the other one it then works....I really hope thats all it is


2000 Club Member
On my solenoid, both small wires come from the western harness. One is power from the controller, and the other has to be ground. Try a small ground lead from that post to the bat, or a metal surface, and see if it then works.


Senior Member
I'd run an 8 gauge wire with at least a 25amp fuse straight from the battery to the motor terminal just to see if the pump motor runs, you could have a stuck brush in the motor?
also check the solenoid mounting plate sometimes that needs to be grounded

SlimJim Z71 Addict
Cary, IL
Okay... if the solenoid is clicking, you know you;ve got power there. Check the wiring going from the solenoid to the pump. Make sure it's not broken, and make sure it's connected to the right spot on the motor/switching unit. Also, check fuses & any fusable links.

As far as the other two wires on the solenoid, I'm guessing one is for power (from your joystick), and the other is for ground. I'd have to see it to be sure. Hang on, I'm gonna put my shoes on and go look at mine...

Okay, I actually have three wires going to mine, other than the heavy "In & Out" wires. Two are on one post, it looks like they come from the plow controls. The other post is going to ground right on the battery. That sounds like your problem.

Also, double check all the wiring on your pump, make sure they're all connected.

Good Luck!



Senior Member
Both of the small wires come from out of the harness.
I know the one thats "hot" is ok so I think it's a bad ground.
I'll run a new one from the battery to the other terminal and see if thats it.
If it works like that ok I'll leave it like that.

My other choice is to trace the wires back through the harness and try to find out where there's a broken one, but I don't have a manual for it with wiring diagrams.

At least it hasn't snowed here yet.....LOL


DaveO Veteran


If the solenoid is clicking, the small wires from the harness are probably OK.

A "solenoid" switch is basically just a high current relay. Most have 4 connections. The 2 "coil" inputs, which are from the controller. Normally one will connect to gnd, the other to a switched "+12V". When you apply the switched +12V, a magnetic field is created, which draws a large contact switch "closed". This is the click you hear.

The other 2 wires(large gauge) are the "switch". These are usually N.O.(normally open), until the coil power is applied, then they close(connect).

The most common failure modes of a solenoid are either the "switch" becomes dirty/carboned and will not conduct large amounts of current anymore. Or the switch "welds" closed, and cannot be turned on/off, as it is stuck on.

As with the older starter solenoids on cars, you can jump across the large terminals to see if the motor works.

Hope this info helps.


[Edited by DaveO on 12-11-2000 at 08:29 PM]

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