Aux Lights - Wiring How To !

/ Aux Lights - Wiring How To ! #1  

Scrambler82

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Tractor
Mahindra Max 28XL, HST, TLB
Not to offend anyone but this is a write up I did for another site.
If you find a problem please let me know, although I have proof read it I always seem to miss something.

Here it is:

Auxiliary Lighting Wiring
By Scrambler82
Any questions: nnf000@gmail.com

This can be applied to any aux lighting, i.e. Off-Road Lights, Fog Lights, Backup Lights, anything with a load (the lights, an AMP), a relay and a power supply (the battery).

Warning - Electrical Safety / Fire Hazard: Size all components by the Amperage Rating of the circuit. This applies to the amperage draw of the lights/component based on the wattage, the relay, the wire, and the fuses. (i.e. 2- 100 watt lights - 200 watt / 12 volts = 16+ amps)

What you will need: (Two 100 Watt Off-Road Lights)

Relay(s) A 30 amp Automotive Four Pin Relay, pins numbered 85, 86, 87, and 30 are the best to use. If you have a relay that has pin 87a, this will work but be aware that pin 87a will have 12V Battery Power when the lights are off; this is good if you are getting creative but not so if a wire or a tool hits it and things start to short out.

10-ga Automotive Wire (12-ga will work for 20 amp or less) Do Not use the Household Wire that is found at the local Hardware Store it is not automotive wire and can deteriorate if oil/fuel gets on it and it is not as flexible making it harder to run through the vehicle. Buy enough Wire to run from the battery to where you want to mount the relays then on to the Lights; no real min or max on this wire length, it will all be considered short runs.

16-ga Automotive Wire (18-ga will work) buy enough to go from the inside-Circuit Panel to where you want to mount your switch, then to the relay under the hood; again No Household wiring.

Dash Switch This is to control the Relay with a low amperage circuit, the switch should be capable of handling 12 volts minimum; a 125 or 250-volt switch will work if it is the type you want. There are too many different types of switches to mention here but for the easiest type and related to the schematic buy a SPST (On-Off) switch.

Fuse Tap - A connector to tap a Circuit on the Circuit Panel inside of your vehicle.

Fuse Holders Two in-line fuse holders, one for a low amperage fuse (2 amps), for 16-ga wire and one for a high amperage fuse (30 or 40 amps) for 10-ga wire

Fuses One 2-amp for the Switch/Relay Circuit and a higher amperage fused based on the total current draw of the Main power. You will need a 25 or 30 amp fuse for the 2 100W lights.

NOTES:
Activating Relay Pin 86 on the Relay is used to activate it and 85 is used for the ground but both wires are required to make the Relay work. Some Relays without pin 85 ground through the mounting hardware. It is a good idea to ground close to the battery or directly to the negative post on the battery.
Main Power from Battery - Use a minimum of a fused 12-ga wire from the battery to pin 30 and from pin 87 to the lights when hooking up 2 - 100 watt lights. It is better to use a heavier gauge wire than a smaller gauge wire, i.e. 10-ga instead of 12-ga. In my opinion there is no such thing as over kill when wiring high current in a vehicle, bigger is better.
Fuses The fuse is there to protect the circuit and all of the components in the circuit and needs to be rated for the smallest component in the circuit plus a small margin for initial draw. MAKE SURE TO USE FUSES.

The Install (Everyone does things a little differently but this is how I do it and it has worked fine for many installs)

Step 1) Mount the Relay under the hood and the Dash Switch where you want them. (Best to keep the relays as close to the battery as possible and within reason)

Step 2) Finding Switch Power Point using a DC Electrical Probe or Multimeter - find the power type you want to control the Switch on the Circuit Panel inside of the vehicle.
a) On all of the time, so the Aux Dash Switch will do the main power control
b) On with the key, this will allow the power to be controlled by the Ignition/Dash Sw. and the lights will never be left on or able to be used without the key.

Hooking up the Switch with a low amperage circuit:

Step 3) Run a fused 16 or 18-ga wire from the power point on the Circuit Panel (Step 2) to one pin on the SPST Dash Switch.

Step 4) From the second pin on the switch run two wires, one will go to pin 85 on the Relay and the second wire will go to the power side of the Indicator Light.
Note: Some Switches come with indicator Lights inside of them and all that is usually needed is an additional wire to ground but everyone is a little different so double check what connection on the switch do what and hook up accordingly.

Step 5) Hook up the Ground of the Indicator Light Most DC lights have two wires, one power coming from the switch and the second is the ground and the ground needs to be connected to a good metal grounded point on the body of the vehicle.
Some ground through the housings, watch it.

Step 6) Connect the Wire from the Switch (Step 4) to pin 85 on the Relay.

Step 7) Run a 16 or 18-ga wire from pin 86 to ground, use some external tooth star washers on the connection to make sure the connection makes contact with new metal.
Note: I like to use a Conductive Contact Paste on the ground connection to keep things cleaner longer.

Test Point

Step 8) At this point you should be able to flip the Dash Switch and hear the Relay click, if you don稚 hear the clicking re-check all of the connections or if you hooked up power to the switch as a Key飽n Power only, then turn on the key. Once you hear the Relay clicking then you are ready to hook up the power to run the lights.

Hooking up Battery Power to run the lights:

Step 9) Run a fused heavy gauge (10 or 12) wire from the battery positive post to Pin 30 on the Relay, make sure to have the higher amperage fuse in-line with this wire.
Note: Mount the fuse close to the battery, this is a safety link and should blow out as first sign of a shorted circuit.

Step 10) Run the same 10 or 12 heavy gauge wire from the Relay, pin 87, to the first Aux light and over to the second Aux light. Allowing for routing the wire and connecting the wire to the second light.

Step 11) Make the connection to the first light - To make a connection, strip some of the sheathing (outside covering) off of the power wire, make sure NOT to nick the strands of wire, and slip a piece of Heat Shrink with adhesive inside, on to the power wire but do not shrink it at this time just slide it over the power wire and out of the way. Twist the Light Wire and the Power Wire from the battery and the wire going to the second light together and solder this connection.
Alt methods:
1) The main power wire can be run as one piece and the first lights can be connected by stripping a small portion of sheathing off but not cut the wire through. Then all you need to do is wrap the Light wire around the power wire and solder.
2) You can use connectors
3) Run two wires from the Relay pin 87, one to each lights there are connectors for this purpose.

Step 13) Make the connection to the second light - Run the wire from the first light to the second, making sure to slide a second piece of Heat Shrink on the wire. Cut the wire to length, solder the connections and clean them, again do not shrink the Heat Shrink just slide it over the joint.

Step 14) Grounding the Lights You can ground them to the closest metal or you can do it the way I do. Run an additional wire, the same gauge as the power wire (10 or 12-ga), from the Lights to the negative side of the battery or a grounding point near the battery that will be connected to the battery.
(With a grounding point near the battery there is less chance to have a bad ground connection and in turn the lights ill burn at there full capacity with less burn outs).

Test Point:
Flip the switch and the lights should come on. If they don稚 you will need to re-check the Power Wire only from the battery to the Relay and then from the Relay to the lights; that is if the Relay is still clicking in step 8.

Notes:
There are too many ifs to state every possible reason for the lights not working but usually if the wiring is OK then you need to check the Fuse or the Light Bulbs, maybe the Relay. If those are OK, re-check the wiring just to be sure, double-check all of the connections.

There are different type of heat shrink and most will work OK but the most important thing to remember is that you want to keep as much dirt and moisture out of the connections as possible. The best way is to use heat shrink with adhesive inside of it and when you shrink it the adhesive will melt and seal the joint.
Make sure the circuit is working correctly before shrinking this type of heat shrink.

The wire gauge that you use will depend on the total current (amperage) draw of the lights, usually based on the wattage of the lights. Using a larger gauge is better than a smaller gauge wire because of safety factors and the larger gauge wire will allow the light to run at their brightest and last the longest.

Always fuse the power wires especially the battery wire going to the relay (pin 30).

Always use a Relay to control the battery power.

I hope this isn稚 too confusing; I can get carried away very easily.

Any questions: nnf000@gmail.com

Schematics - Aux Light Hookup with Indicator Light

_AuxLight.jpg


Schematics posted by SirGCal, Moderator, JeepForum.com.
 
/ Aux Lights - Wiring How To ! #3  
might want to mention to check the capacity of the charging system so as not to overload it. most alternators should not be run at more than 80% rating for long durations.. couple that with the fact that many tractor charge systems are designed with not much fat in them. IE.. whatever the tractor needs to run stock, plus a few amps to recharge the battery wile you work or play.

soundguy
 
/ Aux Lights - Wiring How To ! #4  
Or ....just buy new technology LED lights and wire them straight through a switch ....... Bingo...all done.
 
/ Aux Lights - Wiring How To ! #5  
I can't wait till led technology advanes a bit. big power savings at home too!

soundguy
 
/ Aux Lights - Wiring How To !
  • Thread Starter
#6  
Soundguy said:
I can't wait till led technology advanes a bit. big power savings at home too!

soundguy

Yes LEDs will be nice when the price comes down...
I guess a list LED Lighting would help !
 
/ Aux Lights - Wiring How To ! #7  
I guess the only thing I will add is how you wire the relay.

Most newer stuff puts 12v power to 86 and the switch on 85.

By putting the switch on the ground side, you are running less hot wires. And in the even of a short, NO fire hazard. If it were to short out, the lights would simply come on. It would be a better option if you didnt want the indicator light, cause if you did, you'd either have to pull power off of 87, or run a hot wire to the light and switch that ground as well.

Still an excellent write up though.:thumbsup: Not trying to take anything away from that. Just pointing out that their is another way to wire the relays. And switching the ground side is the "newer school of thought"
 
/ Aux Lights - Wiring How To !
  • Thread Starter
#8  
I guess the only thing I will add is how you wire the relay.
Most newer stuff puts 12v power to 86 and the switch on 85.
By putting the switch on the ground side, you are running less hot wires. And in the even of a short, NO fire hazard. If it were to short out, the lights would simply come on. It would be a better option if you didnt want the indicator light, cause if you did, you'd either have to pull power off of 87, or run a hot wire to the light and switch that ground as well.

Still an excellent write up though.:thumbsup: Not trying to take anything away from that. Just pointing out that their is another way to wire the relays. And switching the ground side is the "newer school of thought"


Switching grounds is something automotive manufacturers have done for some time but this isn’t intended to switch grounds.
Some of these guys would know the difference but most will not (no offense meant) so lets do the KISS thing, "KEEP IT SIMPLE STUPID”.
Now that said, Pins 85 and 86 are fully interchangeable in a DC Circuit, no problem what so ever. Once the switch is thrown and 12V is sent down the wire the coil in the relay will activate either way. I guess what I am saying is there really no "plus or minus" on those pins.
If for some reason there is a short on the power to the relay on either pin from the switch the relay will simple deactivate. IF you have a pin 87A (some relay do and some do not) that pin will become live because it is an Normally Closed Pin (NC).

I think you are putting to much thinking in this, you stated, "It would be a better option if you didnt want the indicator light, cause if you did, you'd either have to pull power off of 87, or run a hot wire to the light and switch that ground as well.?

The indicator light can be placed in a number of positions. One is where it is in the schematics on the load side of the switch. This in turn indicates that there is power coming out of the switch nothing more.
If you connected the indicator light on pin 87 you would need another fuse for it but it then would indicate the relay has latched and there is power coming out of the relay; good idea.
And then there another way, run a wire from the indicator light to the negative side of the light; this would turn on when and IF the light turned on only and it would give you the best information, i.e. the light is on or the light did not go on and you could replace the bulb.
Of course there is the final idea and have no indicator light because if the driver turns on the lights it has to getting dark and if they can not see the lights on then maybe they should not be driving the tractor. LoL.

IMHO this is information in the way I see it and work with it, have been wrong before and will again.
Thanks for the input.
 
/ Aux Lights - Wiring How To ! #9  
Switching grounds is something automotive manufacturers have done for some time but this isn稚 intended to switch grounds.
Some of these guys would know the difference but most will not (no offense meant) so lets do the KISS thing, "KEEP IT SIMPLE STUPID?
Now that said, Pins 85 and 86 are fully interchangeable in a DC Circuit, no problem what so ever. Once the switch is thrown and 12V is sent down the wire the coil in the relay will activate either way. I guess what I am saying is there really no "plus or minus" on those pins.
If for some reason there is a short on the power to the relay on either pin from the switch the relay will simple deactivate. IF you have a pin 87A (some relay do and some do not) that pin will become live because it is an Normally Closed Pin (NC).

I think you are putting to much thinking in this, you stated, "It would be a better option if you didnt want the indicator light, cause if you did, you'd either have to pull power off of 87, or run a hot wire to the light and switch that ground as well.?

The indicator light can be placed in a number of positions. One is where it is in the schematics on the load side of the switch. This in turn indicates that there is power coming out of the switch nothing more.
If you connected the indicator light on pin 87 you would need another fuse for it but it then would indicate the relay has latched and there is power coming out of the relay; good idea.
And then there another way, run a wire from the indicator light to the negative side of the light; this would turn on when and IF the light turned on only and it would give you the best information, i.e. the light is on or the light did not go on and you could replace the bulb.
Of course there is the final idea and have no indicator light because if the driver turns on the lights it has to getting dark and if they can not see the lights on then maybe they should not be driving the tractor. LoL.

IMHO this is information in the way I see it and work with it, have been wrong before and will again.
Thanks for the input.

Switching the ground is still simple. Same amount of wiring, same amount of connections, you are just switching the other side of the circuit.

And since this is a tractor forum, most of us here who would install worklights would probabally opt to NOT install an indicator light. Because it would be very easy to see if they are on or not.

This is just my opinion. If I personally were going to install lights, I'd skip the indicator and switch the ground side. But to each his own.
 
/ Aux Lights - Wiring How To ! #10  
a lamp to let you know your lamps are on.. too cute.. :)

soundguy
 
/ Aux Lights - Wiring How To ! #11  
I've had my work lights get switched on during the day and never realized it. Since my work lights are NOT on the ignition circuit and stay on when motor is not running, this could have been a problem if not for the indicator light
 
/ Aux Lights - Wiring How To ! #12  
I've had my work lights get switched on during the day and never realized it. Since my work lights are NOT on the ignition circuit and stay on when motor is not running, this could have been a problem if not for the indicator light

Just curious- wouldn't you notice your work lights more than an indicator light since the work lights are bigger and brighter?
And consequently wouldn't the situation you mention above be a good reason to put your work lights on the ignition circuit? Or is there a specific reason NOT to have them on the ig circuit?
 
/ Aux Lights - Wiring How To ! #13  
If the worklights are mounted pointing backwards or over your head, you wouldn't know they are on during the daytime.

The ignition circuit is only capable of switching relatively low current loads. Putting in a separate switch that bypasses that allows using a switch that has heavier current handling, and you can use the lights with the key out.

Best way is to use the ignition switch to switch a relay that connects the lights. Better way is the aforementioned LED lighting. Better way again is an electrically powered tractor, but I guess that's a ways off yet.

Jon
 
/ Aux Lights - Wiring How To ! #14  
id go with the ign switch running a relay that then powered a circuit that was used like accy. A reg lamp switch could feed from there and turn on lamps or whatever.

when key is off.. it kills the accy circuit. when on.. key switch is sourcing only a low current.. etc.

soundguy
 
/ Aux Lights - Wiring How To !
  • Thread Starter
#15  
id go with the ign switch running a relay that then powered a circuit that was used like accy. A reg lamp switch could feed from there and turn on lamps or whatever.

when key is off.. it kills the accy circuit. when on.. key switch is sourcing only a low current.. etc.

soundguy

Sometimes you need the lights on without the engine running, well at least maybe you will and if there is an Accessory Position then you are go to go but like mine I do not have the acc position so I want to e covered.


AND to make everyone happy I will redo the schematics and the writeup to remove the indicator light.
I for one like the extra lights on the dash.

ltr
 
/ Aux Lights - Wiring How To ! #16  
my question why not skip the relay, fuse box, indicator light.

get yourself a set of work lights, 20amp or 30amp switch pending on watt of lights. and run wires from lights, to switch, to fuse to battery?

relay to me. would only be useful if i wanted it so i would have to have the key in the ignition. and either turned to accessories or in the on position.
 
/ Aux Lights - Wiring How To ! #17  
One other little item, with the proliferation of electronics in some of our tractors, I would suggest a diode, oriented in the correct direction (non conducting) across the coil of that relay. This will prevent the spike of voltage that occurs when a relay is de-energized from possibly harming other sensitive electronics in the tractor. If the relay already has a built in diode across the coil, then that is great, but be careful of reversing the polarity of the feed to the coil. A diode placed to shunt the back reverse EMF is common in almost any kind of electronics. Just a thought.

James K0UA
 
/ Aux Lights - Wiring How To ! #18  
One other little item, with the proliferation of electronics in some of our tractors, I would suggest a diode, oriented in the correct direction (non conducting) across the coil of that relay. This will prevent the spike of voltage that occurs when a relay is de-energized from possibly harming other sensitive electronics in the tractor. If the relay already has a built in diode across the coil, then that is great, but be careful of reversing the polarity of the feed to the coil. A diode placed to shunt the back reverse EMF is common in almost any kind of electronics. Just a thought.

James K0UA

if yer gonna get that nit picky.. better go add diodes to the start solenoid and all the other relay's burried under the tractor dash.. ( IMHO.. not needed.. )

soundguy
 
/ Aux Lights - Wiring How To ! #19  
My tractor use to be parked outside @ the ol' place....so my best bet then was to run my lights ect. off the ignition switch.....Ampa
 
/ Aux Lights - Wiring How To ! #20  
if yer gonna get that nit picky.. better go add diodes to the start solenoid and all the other relay's burried under the tractor dash.. ( IMHO.. not needed.. )

soundguy

Nitpicky? huh? here is a good link, towards the bottom this exact relay is shown and discussed, a lot of good information here:

Relays

and here is a quote from that page:
Quenching Diodes:
Anytime that a relay coil is driven by a circuit that is not specifically designed to drive a relay, you should use a quenching/suppression diode connected in parallel with the relay coil. The diagram below will show the connection of the diode. Initially, you may think the diode serves no purpose because the voltage applied to the relay cannot pass through the diode. This is true when the relay is energized. The diode comes into play when the power source is removed from the relay coil. When power is applied to the relay coil, a magnetic field is created and energy is stored in the coil. When power is removed, the magnetic field collapses causing a reverse voltage to be generated (it's called inductive kickback or back EMF). The back EMF can easily reach 200 volts. The diode will absorb the reverse voltage spike. This voltage, if not absorbed by the diode, will cause premature failure of switch contacts and may cause the failure of power switching transistors. You can use virtually any type of rectifier or switching diode (i.e. 1N4001, 1N4002, 1N400x... or Radio Shack part #s 276-1101, 276-1102, 276-1103, 276-1104).


And lets see, I have only been working professionally in Electronics for about 38 years, and as a hobby for over 45.. hum... Now in my simple tractor, and probably yours, there probably are no microprocessors, but in a lot of newer tractors there are some. Now if you don't want to add a 59 cent diode to a relay coil, its up to you. But I just wanted to let the folks know there is some danger. IMHO:laughing::laughing:

James K0UA
 

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