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Discussion Starter · #1 ·
Using your head lights can be blinding when they reflect off a snow plow, snowpush or a bucket at night. John Deere does not allow for you to run your work lights alone in the stock configuration. With less than six feet of wire, a 4 connectors and one switch, you can fix this.

To start, remove the cover over the three point and 3rd scv lever. Then remove the other 3 screws holding down the cover that holds all the switches. It helps to move the rubber grommet up on loader lever to gain room. Once under there you will see a few loose plugs that we will use to gain power.

Then there are 4 screws that hold the top of the dash on. Remove them and gain access to the heal light plug. To make it easier, pull gently on it to remove it.

You can see in the pictures the wires and connectors I used. You need a simple spade connector to plug into the factory plugs and three terminal quick connectors. There will be a short wire to go from the power to the switch and a 6 foot piece to go from the switch, down under the floor mat and up into the dash.

Run the longer wire out of harms way next the factory harness under the mat and up into the dash. Once up there slide your quick connector over top of the purple wire in the switch. You may need to loosen up the connector to get it to fit over the spade. (If you wanted the flashers to work alone with this switch, you would attach it to the orange wire). Plug it back onto the switch.

You have a few choices for grabbing power on the rear; beacon, rear wiper or air seat. I use the beacon plug. The center large red wire is a constant power. Using that would allow you to turn the switch on and use the work lights without turning on the key. Please check these out with a meter!

Use your spade connector to slide into the JD switch with the power of your choice. At this point, try things out. Your switch should work and the factory switch should work. Always do this test before putting things back together in case something came loose.

Remove a false switch cover in the place you want you switch and route the two wires for your switch through there. Reinstall all of the switch covers. Plug in your switch and slide it into the slot. From here, you are done.

I use the JD working switch Part # MIA10204 but any switch will work. What we are doing here is using the power from a source to flow to the stock headlamp switch to engage the relay that runs the work lights. Your switch is not running the power the work lights need through it. You are also not back feeding the factory switch, so there is no danger of any issues with this.
 

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Well done. I have my work lights independent of each other and the headlights.
 

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Nice job Brian.
 

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What with the "eepete" name and all, I'm a little embarrassed that it took me a long time to figure out what you're doing, and I'm still fuzzy :think:....

It sounds/looks like there is some way to plug another spade lug into the wire harness plug on the dashboard light switch. It's not clear from your pix (to me) if this is a male or female lug, and suspect that when one got things open this would be clearer. It looks like a female plug...

The rest is clear, you run this wire that connects to the purple wire on the existing in dash light switch to the switches on the right hand side operators console. There is what looks like an 8 position plug with four wires on it, and the big red is constant power and the little red is switched power.

So the exact means of connecting to the existing purple wire on the dashboard light switch not withstanding, so far I'm with you.

But then you say:

What we are doing here is using the power from a source to flow to the stock headlamp switch to engage the relay that runs the work lights. Your switch is not running the power the work lights need through it. You are also not back feeding the factory switch, so there is no danger of any issues with this.

So pulled up the tech manual to help me figure things out. I'm looking at page 244 in the manual. For the 4520, it shows the purple wire coming from the light switch S2 (137A) to fuse F6 and then that continues on purple wire 147A which leaves the diagram on the upper right and continues on the next page (page 245). There we see the wire going to the E3 and E4, right and left work light, with a symbol that is a circle with an X in it (like a rail road crossing).
You can also see this on pages 172 (the switch), page 173 (where we go through fuse F6) and page 175 (where we pick up the rail road crossing symbols for the lights).

I think that the light switch directly drives the lights, not a relay that drives the lights. On page 159 at the beginning of the electrical section, there is a "Reading Electrical Schematics" section. Relays there have very specific symbols, and we see these symbols throughout the schematics for the tractor. The same rail road crossing symbol is used for the tail and turn lights, which are lower powered lights. This makes me think the rail road sign is a light bulb.

So it looks to me like the switch you've installed is driving the work lights directly, and not through a relay. Maybe the 3x20 is different from the 4x20? I guess the next step is to figure out what the small red wire comes from, and what it's load might be intended for to insure that the work lights don't draw too much current from whatever switched source that is. I'll track that down tomorrow AM, it's getting a bit late for me.

The means of connecting to the purple wire are also not clear, but if it's obvious once you're in there, that's OK.

It's a great idea to have an independent switch that turns on the front work lights just like there is an independent switch for the rear work lights. I think I'll be doing this to my tractor. Look at what I've mentioned and let me know if I've missed something or am just plain :cookoo:.

Pete
 

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Discussion Starter · #6 ·
Not being an electrical engineer and able to clearly read the manual, I had to go on information given to me by someone who said they could read them. I was told that there was a relay for all lights on the tractor and it sounds like I am incorrect. The switch I used should be able to handle it. The issue is goingt o be where the switched power lead came from. For me, I also have the rear wiper plug open, so that might be better.

The purple wire on the switch is kind of a weird one. It is not a female connector because it bends around and clips into the switch, but for all intent and purpose, it is flat and the slip on connector will fit in there and be tight with no issue at all. I am connecting to the metal prior to it going into the plug.

I did the same thing on my 3720 and have many hours on it with out a complete melt down. If there is no relay, I might put one in for myself. I can grab the larger power wire to feed the relay and use the switched power to turn on and off the relay allowing me to still have this go off after the key is off.

I am very interested in what you find out!
 

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Ok, I'm really confused.

The owners manual shows the two layouts for the fuse and relay area (the load center). For non-cab tractors, there are two relays, the fuel solenoid and starter. For cab tractors, there are three relays- a new "work light relay" at K3 is shown. On the Open Station tractor, K3 is the starter relay. The wiring harness diagram on page 185 shows only two relays in the load center, so this looks like the harness for the OS tractor. Page 187 similarly shows the load center with just two relays in it.

The next confusing item is that the wire number, 147B and 147C (purple) is shown on the electrical harness for both the rear lighting (page 186) and front lighting (page 185, but it doesn't explicitly call it out as the front lighting). And on page 175 this wire drives what is called the "Right Work Light" and "Left Work Light", no mention as to front or back.

Page 200 shows relay 3 (K3) as the start relay, consistent with the OS load center.

Examination of the light circuit section starting on page 244 shows no work light relay anywhere. There is also no mention of a rear work light option, despite calling it out on the wiring harness detail. The pictures for lights are all OS types of lights.

There is no drawing of a connector with the two red wires and a yellow and white wire as in the pictures. In the section with tests for all the switches in the tractor, there is no work light switch test.

So I'm guess a few things here. The service manual does not correctly show some aspects of the cab wiring. And while it has some of the options (like cruse control and back up alarm), it does not have any data on the work lights.

I'm off to ask my Deere dealer what's up. I bought a service manual for my tractor that does not have the right information in it. I checked on line and the manual I have is the only one they offer.

More to follow...

Pete
 

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Discussion Starter · #8 ·
Just as an FYI. My switch will turn on both front and rear lights. You can turn off the rears by using the rear work light switch installed with that kit.

So I have two work light switches. One to toggle off the rears when the fronts are on (factory) and a second (my mod) to turn on the work lights by them self.
 

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Stopped by the Deere dealer, they wrote up a request on all this and will send it off to the Deere mothership. In a nutshell, the tech manual for the 4520 does not have in information on the load center for the cab version with regard to the work light relay and it's wiring. We'll see what happens....

SWAG time: There is clearly a relay there, and the owners manual calls it out. The rear work light option just takes the front work lights and runs (through the switch in the cab) up to the rear work lights. So I am _guessing_ that there is a relay that is run by the light switch in the cab that powers the work lights. On the OS model, the work lights are powered directly from the switch.

Pete
 

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Ok, I have a better understanding off all this now.

As is often the case in life, my confusion was by my own hand. I'll be giving myself a firm talking to :nunu:.

I ordered the OS version of the tech manual, not the cab version. The OS version does not have relay(s) for the work lights. The cab version of both the 3x20 and 4x20 do have relay(s).

Having figured this out, there are two things that catch my attention:

1) Use the beacon power wire. It's on the same lighting fuse, so when you pull that fuse everything you expect to be dead is dead. There is no way to back feed anything if you have both the dash light switch on "field" and the new "work lights only" switch on.
The beacon lamp switch will have a big red wire, a black wire, and two lugs with an orange wire connected to them. The big red wire is the one to use. When I do mine I'll post a picture of this switch cluster.

2) Fuse the wire installed from the dash light switch that runs down through the cab (as Brian talks about) at each end. This wire is on a 30 amp circuit at each end, and a short in the wire that was ran would be bad. Yeah, you could probably run a 14 gauge wire as it would pop the fuse before the wire would melt but fusing it means easier diagnosis if there is every any problem. If one of the in-line fuses you put in blows, you know it's your wire. If you put in no fuses you will have all the wires in all parts of the work light wiring that could be suspect. I'll be running a 16 gauge 600V. The 600V is just for extra thick insulation for mechanical protection.

The two sizes of wire I tend to stock are 20 gauge 300V for inside a chassis and the 16 gauge 600V for anything exposed.

Again, all this is good only for cab tractors with the relays.

I'll post pictures and parts used when I do this, which hopefully will be some time this year. Sorry for the confusion :dunno: !

Pete
 

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Will try

Brian, thanks to your detailed explanation and ESPECIALLY the excellent pics, I'm going to try doing this myself in the next couple of days. Have your first post directions printed out to use. Any other tips or "watch out for...." type advice? I think not being able to run headlights-worklights independently is short-sighted on JD's part. The headlights are useless for night loader work.
 

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Discussion Starter · #12 ·
IMHO, its a very simple mod to do. Take your time taking off the cover over the three point lever. Make your wire runs neat and enjoy it.

If you need to, pm me and I will give you my number and I will talk you through what ever comes up.:good2:
 

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Thanks, sounds good. Trying to find a switch, local JD does not have them in stock. Tried for other basic on/off switches that the 3x20s have in the cab but no luck. Probably just have to order.
 

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Discussion Starter · #14 ·
If you dont want one that is labeled, Dave has a link to the manufacturer who makes the switches for deere. You can get lighted ones and all kinds of different stuff. They are the identical switch without the label. Much cheaper also.
 

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Thanks for the switch link. I bookmarked it. Very reasonable prices and cool switches. Think I have one on the way from JD (higher priced, of course).
 

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Completed the switch change so that the work lights are independent! Went smooth thanks to Brian's directions and pics. Had a non JD switch from who-knows-when -or-what-other-project it was meant for that fits in the slot. This one lights up when "on". Used the ground from the beacon plug for it. (The lighted ones require a ground). Will probably change the switch in the future so it better matches the ones there but it's good to go for now. Just waiting for the snow predicted for the upcoming weekend. Not sure how much yet. Thanks!
 

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This entire thread has been very interesting and the pictures that Brian provided have been super. I am still waiting for delivery on my 3720 but I have been reading the owner's manual online. I note that the flashers only operate when using the headlights; they do not operate when using the field (work) lights. Is there a simple fix or jumper that I can consider installing to they function when using the work lights? Thanks and great job folks.
 

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I'm looking at the schematic for a cab 4720.

The wire from lug 2 of the light switch (S8) is energized when the lights are in marker or road position. In other words, the flasher are on in marker or road but you knew that. The power for the light switch is right off the battery, which is why the lights work even when the tractor is off.

That line from lug 2 of the light switch (wire 103A Orange for those with the tech manual, page 179) runs off and connects into the instrument control computer (ICC, page 177). The computer has outputs call "RH HAZARD" and "LH HAZARD" which go off to the amber hazard lights on wires 135C and 145C to the amber lights in the cab (page 181, stuff on the top cab harness).

The ICC also has connections to the turn signal switch and the red rear turn lights.

When the tractor is off, you can turn on the hazard lights via the light switch (maker or road position) and the amber lights in the top of the cab blink. When you do this, the power to the ICC is off. If you try the turn signal, it does not work. The rear red lights are also always off.

So I'm _assuming_ based on this behavior that the ICC has some wiring in it such that if it is off and you feed it +battery is will blink the upper cab amber lights. So it's OK to feed this wire that goes into the ICC with un-switched battery.

If the tractor is on, this "default behavior" goes away and it can run the amber lights on it's own, and indeed the turn signal works. The turn signal also runs the red rear turn lights. When the tractor is on, the light switch input to the ICC just lets it know you want the hazard lights on.

So here's what I'd try:

One cheap and dirty possibility: On the light switch, connect pin 4 (the work lights terminal) to pin 2 (the hazard light terminal). When you turn on you fancy new "work lights only" switch, you will also get the hazard lights. Now the down side of this approach is that when you turn on just your hazzard lights, you will get your work lights too. So your light switch will now function like this:

Off - well, everything is off !
Marker (1st position): Hazzard and work lights.
Road (2nd position): Hazzard, head lights, and work lights.
Field (3rd and last position): Hazzard and work lights.

Might be some problems with local laws since you can't go down the road with just hazzard or hazzard and head lights on.

A possible way around this would be to put a diode between pins 4 and 2. Anode to pin 4, cathode to pin 2. I'd take an amp meter (10 amp capacity) and see what the current capacity is. The ICC does have connections to unswitched battery. The question is does it use those connections to power the hazzard lights or does it draw a lot of power from the input the to the ICC from the light switch.

If there is a small amount of power (relay coil type draw in the 250mA or less range) than the diode is a good candidate. If it draws a lot of power, then a relay is also candidate if a suitable capacity diode can't be found.

I would propose that if the pin 4 to pin 2 solution doesn't work or is undesirable (and I know I don't want to give up the light modes I already have) that the next person in messing with a tractor who has an amp meter can take a reading and we can take it from there. I'm sure I can come up with the right diode.

Clear as mud :lol: ?

Pete
 
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