Alan's Plow Controls
Plow control experiment - 2-7-05
I've been playing with a better switch system to control a Sno-Way front plow
and a Snowman pull plow.
Presently using two rocker switch boxes. Reliable but a real bear to manage. I've tried mounting both boxes on a board, too big to hold comfortably. I've lost track of which box I have in my hand and tried to lift the rear plow, lifted the front one instead (it was already up) and backed onto the rear plow causing severe damage.
After playing with the idea, on and off, for most of a year I finally have it worked out.
Meyer Slik-Stik joystick is the main control. I pinned out the contacts and found combinations that would work for the Sno-Way functions. It took a few diodes to keep from backfeeding the wrong circuits but it was fairly straight forward.
I originally ran that into stock Sno-Way weatherpack connectors and proved the theory. Then I was up against needing a way to send control signals to one plow or the other.
I put together a bank of six mini SPDT relays. When those are powered down the control inputs are routed to the front plow through the stock connectors. When the relay bank is powered up the contacts switch to the rear plow.
All functions are identical, stick forward, plow drops, stick back it raises. Same for right and left, either plow angles to discharge in the same direction.
I haven't wired the rear plow yet but I've pinned out the connections and I'm getting the right outputs so it should work fine.
One switch controls the relays, and it defaults to the front plow. In the event of a failure in the relays or harness I can unplug the joystick and plug in two Sno-Way rocker boxes and be back in business.
No pictures yet, but I'll get some the next time I work on it.
I would have liked to use two sticks, but there's just no room. I want the
controls for any plow on the left. That way there is never any hunting for a
switch, one hand stays on the plow control, the other handles steering and
shifting. Since this is an S-10 there isn't room enough for any sort of
enclosure beyond the minimum for one joystick, a toggle for downpressure and a
rocker for front/rear selection.
I'm not knocking anybody who has right handed controls, it's just that I've been working left handed for so long now that it's second nature for me. I've been dealing with two switch boxes, getting cords tangled and trying to keep one on the dash and one in my hand. The last thing I wanted was to have two identical joysticks crowded too close together.
My hope is that I can orient the joystick and the selector so that the selector is right under my thumb so I can check it for position without taking my fingers off the joystick. If the enclosure sticks too far out from the door it will be a kneecapper when the pilot bails out. I may have to put an indicator on the dash so I have a visual cue about the rear plow being engaged but I'm trying to avoid that. Right now there are no extra wires to hook up, everything is done through the stock Sno-Way connectors with a second pair for the pull plow. I even kept the wires to different lengths so I won't have to confirm that I'm hooking things up right. Hopefully this will be idiot proof, then I can work on being a better idiot.
I got the wiring finished up and made an enclosure out of some 1/4" PVC sheet.
It took a while to heat it enough to get it rubbery and then clamp it until it
cooled and held shape. Here is the whole shebang on the door of my 91 S-10.
Joystick in the middle, above it is the downpressure switch and the dp pilot light. The pilot is currently not operating, I can run without it and it can wait for a warmer day. At the bottom is the rocker for front/rear selection. The way the housing came out it sits lower than the armrest and the heel of your hand sits on the front of the switch, so it trends to default to front operation. If you bring your hand back just a little and press down it switches to rear plow function.
Had a hell of a time getting the non-dp snowman power pack to work with the Snow-Way outputs. up, left and right all need both power to the motor and valve operation on the Snowman, the Sno-Way has no up valve, if the motor runs the plow goes up unless there is another input. Three diodes serve to isolate the valve functions from motor control for now, once I put the Sno-Way power pack on I'll have both dp and identical control functions.
This box holds a bank of relays, six in all, that swap function input to
either plow. In the event of a failure I can go back to the stock control
boxes by unplugging this whole harness and putting the stock controls back in
place. Hopefully won't ever need to but the ability is there, just in case.
The box is 2x3x6 and will just fit on the little shelf under the dash. Once I
am comfortable with it I'll stick some velcro on it to hold it in place and
add some fastening points under the steering column to keep the wires out of
With a storm due in tomorrow night, and the season getting short, I really wanted to have this working so I could test it this year. There's a lot of "stuff" involved and a boatload of connections and I'd rather proof test this thing now than have to add it to things that could act up next fall.
Project complete - 4-1-05
Knowing that the concept was sound and the wiring was functional I thought it
best to wait until after snow season to start the conversion to a DP power
unit. With the season over (I hope) I got into that part of the project.
Some parts of it went slick as could be, almost too easy, in fact. But,, when things got ugly they got UGLY! I had to extend the mounting plate for the power pack, no big deal. The power unit came off a Sno-Way Series 24 plow that Garagekeeper found for me, thanks again, John. The cylinder came off another Sno-Way, a Lobo that I picked up last summer to go on another full size truck.
After I got the cylinder on the God of Ugly came by to check things out.
I ran a harness from the rear bumper along the frame and up into the cab, tied it into the wires off the relay box and checked it out with a test light and it pinned out OK. The plow connector is another Sno-Way part, so I have the waterproof plug that matches the stock (for Sno-Way) plow side of the harness.
I knew it was going to be a close fit between the pump motor and one of the hoses on the cylinder. I said to myself "Self, ya gotta watch that the first time you raise the plow!" Being all grinning and giggly over how well my wiring had gone I hit the switch, raised the plow and wiped the hose off on the motor housing. That was when I saw the God of Ugly sneaking around the corner of the shed, snickering.
Three hours later I was putting a new hose on. I had to cut the base end of the cylinder off, where it is solid rod, rotate it 90° and weld it back on. That gets the hoses coming off the top of the cylinder instead of off the side. It's still pretty tight in there, but everything clears now.
Downpressure works fine, the back of the truck comes up about 2" so I'm guessing 250-300 lbs of extra weight on the plow. It won't get to see snow until next season but I tried scraping a gravel drive with it and it's not too aggressive, the edge doesn't dig in bad enough to trip the blade. I tore a couple snow banks apart and it's certainly working better than it was with just its' own weight to hold it down.
Only time will tell if it was worth the effort but at this point it's a definite maybe with a tendency towards yes.
Off to the next project!
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All photos and text ©2003 Alan Nadeau, All rights reserved. Used with Permission.