# Plow lights only come on when the pump activates



## Tjkobie (Jan 10, 2017)

Looking for some help, please. I bought a used 2001 Dodge Ram 1500 with a Western MVP Ultramount with Isolation Module Light System. I am brand new to plowing any only wanting to use this for very light plowing such as my driveway and one neighbor's driveway. I understand the 1500 is not exactly designed for plowing.

My issue is that the plow lights only come on when the pump activates, for example, I raise or move the plow side to side. The parking lights on the plow always work. If I unplug the harness, the truck lights come back on and work as they are supposed to. Has anybody experienced this and can you please provide some troubleshooting tips? Any advice is greatly appreciated. Thanks fella's.


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## Tjkobie (Jan 10, 2017)

Tjkobie said:


> Looking for some help, please. I bought a used 2001 Dodge Ram 1500 with a Western MVP Ultramount with Isolation Module Light System. I am brand new to plowing any only wanting to use this for very light plowing such as my driveway and one neighbor's driveway. I understand the 1500 is not exactly designed for plowing.
> 
> My issue is that the plow lights only come on when the pump activates, for example, I raise or move the plow side to side. The parking lights on the plow always work. If I unplug the harness, the truck lights come back on and work as they are supposed to. Has anybody experienced this and can you please provide some troubleshooting tips? Any advice is greatly appreciated. Thanks fella's.


I forgot to mention that there seems to be a draw on the electrical system when I move the joystick and activate the pump. For example, the heater blower motor slows down considerably and if I hold the joystick long enough, I can see the volt gauge drop. Is this because the stock alternator for the 1500 isn't capable of producing enough juice for the plow?


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## ktfbgb (Jan 31, 2016)

Tjkobie said:


> I forgot to mention that there seems to be a draw on the electrical system when I move the joystick and activate the pump. For example, the heater blower motor slows down considerably and if I hold the joystick long enough, I can see the volt gauge drop. Is this because the stock alternator for the 1500 isn't capable of producing enough juice for the plow?


Lots of reasons for this. How old is the battery? What size alternator on the truck?

No idea on the headlights but someone on here will help with that.


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## Randall Ave (Oct 29, 2014)

A little more detail needed. No plow connected, all the truck lights work correctly. With plow on no lights on plow until you operate it.


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## mishnick (Jan 7, 2011)

This is a three plug (at the grill) system right?
All late model ultramount isolation module setups have independent wiring for the plow lights. That is to say there is no connection between functions and lights other than the isolation module itself. Try a new isolation module. I think something inside is crossing over between control and lights. Can't be a bad light ground because the park lights work. Beg, borrow steal or buy an ISO mod and see if that fixes it. It's easy to swap, three cable plugs only. Sometimes it's hidden behind a headlight.


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## kimber750 (Sep 19, 2011)

Since this plow switches ground for functions check your grounds.


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## kimber750 (Sep 19, 2011)

mishnick said:


> This is a three plug (at the grill) system right?
> All late model ultramount isolation module setups have independent wiring for the plow lights. That is to say there is no connection between functions and lights other than the isolation module itself. Try a new isolation module. I think something inside is crossing over between control and lights. Can't be a bad light ground because the park lights work. Beg, borrow steal or buy an ISO mod and see if that fixes it. It's easy to swap, three cable plugs only. Sometimes it's hidden behind a headlight.


Park lights and headlights have separate grounds. Park goes to neg terminal on motor, headlights dont.

OP start with the two single connectors, one by module and one near relay.


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## Tjkobie (Jan 10, 2017)

Thanks for the feedback. For more information, this is a 2 plug system. When the plugs are disconnected, all lights work as they should (truck side). When plow is connected (both plugs), I have interior lights, parking lights, and turn signal lights (truck side and plow side), but no headlights (plow side).

When I raise or move the plow, the plow headlights come on when the pump moved the plow and turn off as soon I release the joystick.

I hope this additional information is useful. I appreciate the help! I'll post a video


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## kimber750 (Sep 19, 2011)

Tjkobie said:


> Thanks for the feedback. For more information, this is a 2 plug system. When the plugs are disconnected, all lights work as they should (truck side). When plow is connected (both plugs), I have interior lights, parking lights, and turn signal lights (truck side and plow side), but no headlights (plow side).
> 
> When I raise or move the plow, the plow headlights come on when the pump moved the plow and turn off as soon I release the joystick.
> 
> I hope this additional information is useful. I appreciate the help! I'll post a video


2 plug? MVP plus or MVP 3? How many pins on control plug?


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## Tjkobie (Jan 10, 2017)

Looks like the video was too large. I am not quite sure how many pins but I can check in a day or so. Again, I appreciate the help!


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## 1olddogtwo (Aug 6, 2007)

Have to post to YouTube then post link.

As asked, what type of plow?


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## mishnick (Jan 7, 2011)

Two plug with the 3 port isolation module. That has to be multiplex. There is only one main ground in that system and the park lights share it with everything else. There may be multiple grounds for different lights in the cable from plow lights to isolation module (two cables and grill plug but in series) but after the isolation module they all share a single ground connection via the black/org wire in the control harness and then through the battery cable to battery (sometimes main ground is on the engine block). This is off the top of my head, not looking at schematics but I am pretty sure about details.


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## Randall Ave (Oct 29, 2014)

Do you have an ohm meter and a wiring diagram. Post a picture of the plow.


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