Sounds like a ground problem, go on Westerns web and get a diagram of they system. Check all the grounds and make sure the connections are all in the proper place. Have seen body shops make the wrong connections when making a repair on a plow vehicle.

 

check these wires to make sure they are correct

These wires are located at the lights

Purple wire = pass side turn signal
Gray wire = driver side turn signal

Brown wire (without cab markers) = driver parking light
Gray wire (with cab markers) = driver side parking light

Relays (low). wire should be as follow
85=black/ with orange stripe
86= brown
87= black
87a = orange wire (low beam)
30= yellow

Relay (high)
85= black with orange stripe
86= brown
87=white
87a=red (high beam)
30=green

Solenoid (motor relay) wire should be as follow

Two main lugs are positive..One from the battery, the other goes to the plow motor

Small terminals.

brown with red strip to one small terminal (from the controller harness)

orange with black stripe to the other terminal (this is the ground for the plow frame, plow lights, plow signals, and from the controller)

Schematic (pg #8 in the pdf)

PDF
View attachment 2003f350_67802_092002.pdf

Let us know what happens.........Check the wiring. The parking wires activates the relays to switch over from vehicle, to plow lights. Also check the orange/black wire..this is the ground wire. Some vehicle also have to have this wire attach to the negative post on the battery.

 

Ok guys. I was unable to find a ground wire problem. The one thing I didn't mention before was that when I turn the plow lights on only the left parking light comes on. When I took the ground loose from the solenoid that one light did go off. So I concluded from that the ground is ok but I appreciate additional comments. The wiring is hooked up correctly on the high and low beam relays. The only question I had was I couldn't find where the gray wire goes to that goes to the park/turn harness. It goes into the plow harness but looks like two wires go down into the frame but I can't tell where they go from there. according to the schematic it is supposed to go to truck harness. Let me know what you guys think I should do from here. Thanks

 

I guess you didn't read post #3 correctly..

Brown wire (without cab markers) = driver parking light
Gray wire (with cab markers) = driver side parking light

If the orange/black (ground wire) is attach to the neg terminal on the battery, unhook it and see what happens?? Also check the connector plug (grill) to see if the pins are bent or broken..

 

When I unhook the orange and black wire from the neg. terminal it kills the only plow light that is on. None of the pins in the plug are bent or broken. It doesn't make sense that only the one light works. I am going to try and trace the gray wire as I have cab lights and make sure it isn't shorted. Could that be an issue? Do you have any other ideas?

 

orange/black stripe wire is a ground wire.. That wire also should be grounded to the plow as well.. The motor relay (solenoid) should be ground to the wheel well, and orange/stripe black wire should be connected to the small terminal on the solenoid..

What do you mean by " kill the only plow light on"??

Let do something different........Let make believe this is a new system, and you are getting ready to hook up the, LIGHT harness, the wires to the parking light, and the signal light.

The "TWO" gray wires. The one that comes out of the park or turn harness (turn signal application) go to the driver side turn signal bulb. The other gray wire should come from the park or turn (car marker / park application) and tie into the parking bulb on the driver side.

Follow the wiring schematics..You can trace the wires using the schematic.. Just make believe your just installing the harness...

check the connectors for the light that connect into the OEM harness..Make sure they are plug in correctly..

 

Ok. I was doing like you said, pretend I'm installing the harness. I had the lights and blinker on while doing it and momentarily the headlights stopped blinking and the plow turn started working. The plow lights didn't turn on but that momentary "fix" tells me the wires I was messing with on the drivers side specifically the gray going to the drivers turn and the passenger turn may be the problem. My next question is if any of you have an easy way to access the park and turn lights. It looks to me like pulling the batteries out is the best way. Do you know if there's a way to get to them from the front? With all the wiring stuffed down on the drivers side and the plugs I have to believe there is a bare or pinched wire or a loose ground. According to the schematic I see a ground coming off the park and turn. Can you tell me how or where it is grounded? Again, any help is appreciated and I appreciate the help you have already given.
Thanks

 

The "gray" might not be secure (there should be a bullet connector) to the driver side turn signal wire.. I can not tell you if there is a faster way but maybe to remove the grill, or remove the battery. As for the ground for the turn/ parking lights, could be running through the OEM harness..

You are on the right track..