1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

Ultra mount mpv problem

Discussion in 'Western Plows Discussion' started by Gman1200hd, Nov 10, 2014.

  1. Gman1200hd

    Gman1200hd Member
    Messages: 35

    hi guys I have a 8.6 ultra mount mpv with the 3 plugs at the grill and 4 port ISO box up ,down,v,scoop,left wing ,right wing all work but the plow won't turn left or right in the straight blade mode it also has the hand held control and help would be great
     
  2. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    This is a pretty easy diagnosis, the S5 valve is failing. S5 is only activated for left and right straight blade mode. So either the valve is stuck or there is an electrical problem on the S5 activator wire. The S5 is under the bottom right valve cover, when you take the cover off it is by itself. The other covers have either three or two valves. Get someone to hit the right or left turn on the control while you hold a screw driver tip to the end of the coil. If power is being sent to the coil the magnetism will attract the screw driver. (but be careful not to get caught behind the blade when it moves! Consider disconnecting the wire from the + terminal on the motor so it doesn't spin.) If you get magnetism then remove the coil nut, then pull the coil and finally remove and replace the valve cartridge, it looks a lot like a spark plug. If there is no magnetism then you have to work your way back along the wire to the controller to see where it's broken. Make sure both wires are securely connected to the coil too. This is a common + so one wire to the coil should be hot when your truck key is on. The controller grounds out the other wire to complete the circuit. Check the pins in the control grill plug. Look for pins broken off or corrosion. If you have access to a different controller try substituting with a known good one. If those things are all good then you have to pull the control harness and look for a spot where friction has worn through and damaged one wire. That wire will be blue with an orange tracer.
    My guess would be a bad valve cartridge. When you pull the coil nut, the black coil should come off pretty easy. If it comes off hard the coil stem is probably swollen or bent indicating the valve is damaged from over pressure. If you take the valve out, put the coil back on and jumper it to 12 v or touch a 9 v battery to the terminals, you should hear a distinct click if it's working. (careful not to get oil in your eye! They tend to squirt when you click them)

    Here is a link to the MVP mechanic's guide http://library.westernplows.com/westernplows/pdffiles/28270.00_070105.pdf
     
    Last edited: Nov 11, 2014
  3. Gman1200hd

    Gman1200hd Member
    Messages: 35

    Thanks for the reply I'll have to try that do you have or know where to find a list of what each coil does I only seem to find the straight blade not the v plow diagram thanks again
     
  4. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,924

    Westerns website under library.
     
    Last edited: Nov 11, 2014
  5. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    look on page 20 of the link I sent above. This page shows physical locations of the valves and the chart shows what valve operates for what function. Page 37 shows a hydraulic schematic, following pages break down how the valves allow fluid flow for each function.
     
  6. Gman1200hd

    Gman1200hd Member
    Messages: 35

    Thanks for the help finely had time to get the truck in the shop today and it was a bad s5 coil sorry it took me so long to reply back thanks again for the help. :mechanic: