# Western Unimount Headlight problems???



## davedev (Jan 17, 2016)

2001 Ford f250 with a 8 Foot unimount on truck since new. I have owned truck for 7 years and never a problem. This year Hook plow up, plow works fine but headlights wouldn't switch to plow lights. All other lights worked. Replaced 9 pin plow side and truck ends and now all lights work. Problem now is when headlights are on plow will not work correctly. Plow will angle opposite, motor runs constantly or when I hit the high beams the plow will drop. I turn off headlight switch and plow works fine again. I think I have checked all wiring and replaced solenoid, cleaned every connection I can think of but am confused now. Any suggestions where to go next are appreciated


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## FourDiamond (Nov 23, 2011)

Is this a three plug isolation module set-up or two plug relay system?


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## davedev (Jan 17, 2016)

It is a two plug relay system


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## dieselss (Jan 3, 2008)

When you wired in the new 9 pin connectors are you 100% you did it exactly like the schematic? 
Also....what made you go right for the connectors without any testing?


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## davedev (Jan 17, 2016)

The 9 pin connectors were original and plastic became hard and brittle. I was careful over the years with them but I questioned 3 pins that I thought looked sketchy. If I wiggled plug it seemed loose and parking lights would blink.


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## davedev (Jan 17, 2016)

I did test relays, The two I am aware of and they do click. I cleaned all terminals and applied dielectric grease to all connections. Replaced solenoid because that was original and plastic was brittle and while attempting to clean terminals the plastic cracked. I have wired ends on plows for years and I am positive I wired correctly. All wires were color matched to old one.


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## davedev (Jan 17, 2016)

If I unplug the brown/orange wire from relay with the 9 pin plugged in so the headlights switch back to the truck headlights the plow works fine. Only problem is when the Plow headlights are on. The plow works fine with just parking lights on.


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## FourDiamond (Nov 23, 2011)

I sounds like the plug is miswired. Try the truck side plug, and test each wired to insure its tied to the proper function. You'll need a good test light and someone to help, but that is where I'd start. If all functions, ie plow goes left/ right, up/down, and the lights work, but their not operating with the proper controller functions. Then is it's a mis-wired plug. If the truck side works, they do the same at the plow side connections. Good luck, and keep us updated.


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## davedev (Jan 17, 2016)

Thanks, will keep updated. Hopefully try tomorrow. Confused because this was the problem before I cut the original plugs off to replace. I had intermittent parking light problems and plow light issues but after I replaced both 9 pin plugs all light work great but have issue with plow controls with plow headlights on. Had someone tell me that it was a ground issue. Have not changed any wires from their original places but he tells me the negative side of battery is neutral and not a good ground. Should I add a jumper to the body for a substantial ground? Just throwing it out there. Thanks for the help.


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## Randall Ave (Oct 29, 2014)

The Neg side of battery is neutral and not a good ground? I have never heard that one before. Make sure your connections are all clean, Do you have an OHM meter. Pin out your harness on the plow side, then the truck side. The ground circuit could be backfeeding current with lights on. Run a ground strap right from the plow motor to the battery and try that.


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## dieselss (Jan 3, 2008)

Parking lights go from the truck straight to the plow. So either, the splicing job at the parking lights, wiring, or the grounds at the pump, or inside the headlights. 
The male pins at the grill can be spread out if there losing contact.
Edit....there is a branch off the plow parking light that goes to the headlight relay to energize them to send power to the plow lights


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## davedev (Jan 17, 2016)

Thanks for all the replies.. I will try today. The plow lights are newer and have worked fine for 2 years. I did check inside them for corrosion and they were spotless. I have not tried putting a jumper from the negative side of motor to the battery negative but will try that today. I was thinking it seemed like it was backfeeding somehow but never had this issue before and didn't know where to start.


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