Is this mod necessary? You be the judge....

Stock backup lights:



Stock backup lights with 2 100-watt tractor flood lights:




I have always needed more backup light, as the stock backup lights provide inadequate illumination through the window tint in remote areas. I have also noticed that many other members of this forum desire more backup light, so I decided to make a little "how-to".

I initially made the same mistake others have made on this forum - I installed aftermarket "driving" lights and powered them directly from the stock backup lights. The result was extremely disappointing, as both the stock lights AND the add-on lights were dimmer than expected.

I made two mistakes. First, "driving" or "fog" lights emit a narrow beam which is not suitable for the purpose of backup lights. You need a "flood" or "trapezoid" pattern. Second, the add-on lights required more power than the stock backup light circuit could supply. You need a dedicated circuit designed to handle the load, using a relay which is switched by the stock backup lights.

I therefore bought 2 "flood" pattern lights desiged for use on tractors (about $10 each), replaced the standard 55W bulbs with 100W bulbs, and ceated the electrical circuits needed to provide the power these lights require.

I know others have done modifications similar to mine, but I have not found detailed step-by-step instructions on how to do this. This is very simple once you know how to do it, and I hope that others will be able to benefit from my experience.

My photo album provides further details.

Hope this helps...

 

I did the mod but later ripped most of it out. I used two cheap 55w driving lights and I did make a deicated circuit. My mistake was that I didn't use a relay, and I pulled my power from a used fuse in the fuse box. One rainy night I turned them on and the top of the switch came off in my hand. I was only going right down the road at 1am so I left them on. Came back home 10 minutes later and the swithc was smoking. I quickly pulled the fuse and all the wires loose from the switch. I never hooked them back up so the lights got all rusted and moisture inside. I do plan on a new set but plan to do it right.
As for the wiring I need some help. I do not want mine to come on with the stock backups. I might want to use them at a standstill hooking a trailer up or whatnot. How would I go about wiring in a relay in this case? Where should I pull my power from? I hate having 10 different wires going to the battery, lookin all nasty and stuff. I thought about tapping on the the start solenoid on the passenger side. Is this a good spot or should I just tap a unused spot in one of the fuse boxes.?

 

This has been one of the most informative and detailed article that I've seen. Good work LowcountryLariat

 

KYFordFreak:
Sounds like you were running your power straight through the switch. Don't know what switch you were using, but I'll bet it wasn't designed to handle the 9 or so amps your lights were drawing - at least not for very long, as you found out!

I agree with you -- I don't like multiple wires tapped into the battery. The only thing I have on my battery is my subwoofer. The power I'm pulling from is the main +12V lead which runs into the stock fuse block. That 12V power goes straight to the lights, by way of the inline 20A fuse and the relay. I chose this location because it should be able to handle just about any load you give it, it's much safer than trying to tap into an existing circuit, and it's close to the grommet in the firewall.

By the way, I'm already thinking of changing this around so I can also switch the lights on manually as you describe -- I might have time to do this in the next week... I think I would tap power off the trailer wiring harness, and use the lead I ran from the front of the truck as my switch lead. I would have to add a couple of diodes... If I do this, I'll post the pics.

chesterc:
thanks... it certainly works well for me.

 

Gentlemen,

This was one of the first mods I did 2+ yrs. ago.

I too learned the lesson about the type of lamp or fixture to use (flood or trap. - NOT driving or fog, etc.). I can't image trying to back-up without them!

My right way:

The lamps are hung with stout sleel brackets below the bumper just to the inside of the tires ( to avoid additional road debris be slung at them).

I ran a constant 12 volt (12 ga.) wire from the drivers side underhood fuse box down the left side frame rail to the void behind the left tail light assembly. The wire has a 30 amp in-line fuse near the tap and is protected by additional "wire loom", well tied to the frame, and strain relieved along the way.

There (behind the tail light assembly), I installed the relay and made the required connections to trigger the relay when the factory lights come on. This keeps the relay dry and close to the lamps.

My install does not include a switch for operating them manually but to do so would only require one more wire to the relay from a low current, switched +12 source.

As I am reading these discussions I am puzzled by the use of diodes. Please understand I am well aware of their properties but...

Why & how are you using them?...


Thanks XLT_D

.

 

XLT_D:

One diode (D1) would prevent the switch from activating the stock backup lights. I suppose this may not be a problem if you don't mind all 4 lights on at once, I only worry about the switch being overloaded/overheated by the current drawn from the 2 stock lights and the relay (especially if lights are left on for a long time). Do you think this would be a problem? If not I suppose you don't need D1.

A second diode (D2) would prevent back-current through the switch in the instance where you are in reverse while the switch is in the "ON" position. Would this lead to problems without a diode? To be honest I'm not sure.

I think the circuit would work without either diode as you mention, but I thought this might be the 'cleaner' way to do it. However, I'm no electrician, and if diodes are not necessary the mod would be much simpler...

Circuit I have now:


Circuit with diodes:


... let me know what you think, because I now want to add a switch for my lights.

 

LcL,

This is always tough to explain "over the web" but let me try:

There's no problem with the factory lights being illuminated along with the added ones as long as your set-up (wire size, fuse, etc.) is capable of handling the total current.

Remember, the whole point here is that you are running at least one, fused protected, additional heavy gage wire to the rear, and a relay, for supplying the +12 (current) to the added lamps.

The relay's contacts should be rated for 30 amps and thus can be turned on for as long as you want.

This additional heavy gage wire is connected to a +12 volt source and fused at one end, the other end is connected to the relay's "common" contact terminal.

The relay's "normally open" contact is connected to one side of the added lamps (the other side of the lamps is connected to ground).

The relay's trigger coil has two contacts, connect one side to ground and the other side to the factory back-up signal (switched +12).

The relay, triggered by the factory lamps, switches current to the added lamps and all four illuminate.


If you don't want both the factory and added lamps on,

when switched manually by an additional switch,

then use the D1 diode between the the back-up lamp signal and the relay trigger.

D2 is not needed.


This describes my set-up with the relay at the REAR of the truck.

Many other variations are possible but make sure all your electrical components are rated for about 2 times the intended use.

Except for fuses... they should be ABOUT 1.5 times intended use, i.e. 10 amp draw - use 15 amp fuse.

XLT_D

.

 

I guess the only reason I thought about diodes was to prevent having the current for the factory backup lights running through a switch on my dash. I wanted the load on the switch to be minimal so it wouldn't heat up. The factory lights would not run off the relay "load" power, but run directly from the switched lead. However, after I considered it, I realized that the factory lights only draw about 4 amps, and my switch/leads are rated for 20 amps, so this should be more than enough to run the factory lights through the switch.

So... I did it today, installed a switch in the dash, no silly diodes... works great! All 4 lights on in reverse, and also when the dash switch is on while in park or any gear...

In order to prevent running another wire to the back, I pulled power for the relay from the trailer harness +12V lead (orange on my truck). I then ran the 14-gauge I previously added (from the accessory fuse block) through the switch on the dash, and tapped into the relay "switch" lead which came from the factory backup lights.

Hope this is clear... Thanks for making me think it through XLT_D, saved me some work...

 

 

Yes my switch was handling the power. It was rated at 15amps so I thought it would hold it. Wrong... learned the hard way.
So now yours still come on with the factory lights all the time but you added the function to turn them on manually. Don't you think that in some situations 100w or even 55w of backup light might be offensive or dangerous to other drivers? That;s the reason I was just going to put them on a switch and control the lights myself.
I guess you could do a 3 postion type deal. Where the addons light with the stock backups, light up manually, and then the third they stay off no matter what. I'm not thinking clearly enough right now to wire something like that up. I'm sure you could use a like a SPDT type switch and do it somehow.
What about my case where I just want to use a swithc and relay? I know that sounds simple but I can't remember how to do that. I would use a 30a 4 prong relay with a lighted rocker switch that has 3 prongs ( PWR, GRND, and ACC). How do I wire that so the relay handles the load? If it's too hard to explain in words don't worry my mind will clear up and I'll figure it out.

 

KY:

The switch I added is just intended for me to be able to use the lights for brief periods when I need to light up the area while I'm working outside my truck - that way I can have bright white light while the truck is in park. I can't imagine how the lights would ever interfere with another driver - even if I'm backing out of a space in a parking lot at night it should be no different than someone driving by with headlights on. It would be illegal and unwise to switch on the lights while on the road.

I suppose you could use a heavy switch to control power to the relay if you were really worried about this. That would defeat the one of the main purposes of the relay, though.

 

LcL,

I wired my aux backup lights with the two diodes as you did. But I also fused each at 3 amps (overkill) and the 2 aux lights (55W/each) were fused at 15amps. My thought with the diodes was that if there was a short in either switch wire, the other could still turn the realy/lights on. My cab switch also has a built in light, so is illuminated when the switch is on.

It's been working flawless with out a problem for the last 1.5 years. Hunting, fishing, using trailers at night, I think every truck should have them. JMHO


http://www.kchilites.com/acb/showdet..._ID=11&CATID=4