Headlight Harness Relay Upgrade: Step-by-Step Illustrated DIY write-up
 

This thread is to help beginners. That's why I wrote "beginner" in the title. Most here will consider this overkill.
But, just saying "Dude, harness install is dead simple, LOLZ" does not actually teach a beginner how to do anything.
B/c even something as simple as a rusted screw can stop a beginner with limited tools in his tracks.
Hopefully, this write-up will be useful for someone else going forward, and answer the questions I had myself.
Before I did this DIY, I had no idea what a relay even was.
Now, I understand their purpose and the basic idea of why a direct to battery harness with relayed switch is a better solution.

I went through the effort of writing up a very detailed how-to b/c I personally like to see all the steps before attempting a job.
I try to understand what I am getting into, and what problems I may encounter, and if it's a reasonable project to attempt with the basic tools I have.
If you found this write-up helpful, and the details and photos I've you the confidence to try this, please bump the thread, and share your results.

This job took me about 3 hours. A couple of obstacles that no one mentions:

1. One stripped screw will double the time required to do this job (screw extractors, cutting wheel dremel, angle grinder, and various drill bits)
   Do not even think about working on a Jeep if you don't own these tools.
2. It was also unclear where to ground the new grounds. Had to try a few places.
3. I also tried a few different places to mount the relays.
4. B/c of this, I had to redo the routing of the wiring a couple of times.
5. It was also hard to unplug the headlights. This took longer than expected, and I had to use a screwdriver.

PARTS:

I ordered this harness from Ebay for $36.
Some people have complained about the Putco relays. The Putco also does not have a fuse.
Others talk about splicing in better relays, but I'm no electrician. For another $10, I went with this, which is cheaper than splicing in relays to the $25 Putco.
Some have also said the Putco is short. I found the extra length to be helpful while snaking these cables around.
http://i44.tinypic.com/33vkcbn.jpg

Here are the headlights for $44
These also come with the bulbs, so it's one less thing to have to learn about.
Make sure you order DOT approved, otherwise you might not pass inspection.
The Ebay seller has Euro "E" that are not USA legal, and he omits that little detail in his ad.
http://i44.tinypic.com/25yvu6r.jpg


STEPS:

1) Disconnect the battery. You can just black negative terminal. Put a sock over it so it doesn't reconnect on accident.

2) Remove the headlight bezels. There are 2 screws on each side.
3) Remove the grille. There are 4 screws.

http://i39.tinypic.com/1693mmd.jpg http://i39.tinypic.com/kebzur.jpg http://i44.tinypic.com/2vazh5l.jpg

4) Remove the 4 screws that hold the headlight retainer bezel.
These are rusted and you will need to press hard to break them free.
I used PB blaster for a few days before the weekend.
One of my screws was stripped.
This added at least an hour to this job.
If this happens to you, you'll need to remove the turn signals out of the way before you begin to battle that screw.

First I tried screw extractors.
They are complete garbage and didn't do a thing.
Or, maybe I don't know how to use them.
I tried to use them in my drill, and they did nothing but carve a nice circle into the screw head.
Basically did what a (crappy) drill bit would do.
http://i39.tinypic.com/son8gp.jpg

I then tried a dremel cutting wheel.
I was unable to get it flush enough, so it made no difference, and the screw still held the ring in.
http://i44.tinypic.com/23lgxz.jpg http://i40.tinypic.com/1zv7czm.jpg

I then tried a drill bit. It also did nothing.
When I did it, it just made a round cavity in the screw head.
And the hacked up screw still held the retainer ring firmly in place.
I think I might need to ask a professional mechanic to show me how to drill out a screw.
Or, next time, I will try an angle grinder and just obliterate the screw head entirely.

So, I gave up and realized that drilling out a screw is beyond my experience & ability level.
Instead, since I had gotten 3 out of 4 screws out, I just bent the retainer ring down to free the headlight.
http://i41.tinypic.com/ivzn9u.jpg

Eventually, I just got pissed and ripped the retainer ring off the screw.
I tried to get this screw out by just bending it from behind with needlenose, but it was frozen solid.
http://i44.tinypic.com/fm830i.jpg

5) Next, it's time to unplug the old headlights.
The plugs have been fastened for 15 years, so they are really stuck on.
Also, you need to pry apart the clip.
I had to use a screwdriver to gently pry off the clip.
There was no way to do it with bare hands.
http://i42.tinypic.com/21n30vl.jpg http://i39.tinypic.com/wme8go.jpg http://i44.tinypic.com/903rtg.jpg

6) Now, you need to connect the new harness.
Make sure you snake the cables backwards so you can tuck them away.
I hooked the red power to the fuse box power bolt.
http://i41.tinypic.com/22mgr5.jpg

7) Snake the cables to where they need to go.
This will take some time to see how it's routed.
Snake the driver's side across the grill where the original wiring goes.
In the grille, zip tie the long cable to the old cable
Feed each bulb connector into each housing.
Tip: Get under the Jeep to see where to route them.
You will connect the new harness into the old headlight socket.
http://i39.tinypic.com/2vt9kd2.jpg http://i41.tinypic.com/160zh2d.jpg http://i42.tinypic.com/2zhmujs.jpg

8) Each new bulb socket has a ground wire.
I connected the passenger ground to the same ground where the negative battery terminal connects to.
http://i39.tinypic.com/2418sp5.jpg

I was confused where to ground the driver's side.
Here is what I did, and I don't know if that is correct.
http://i41.tinypic.com/2094nc7.jpg http://i40.tinypic.com/2mrf7fc.jpg

9) Connect the new headlights to the new sockets.
You also need to install the bulb into the headlight.
The thing that you remove can be thrown away.
Don't forget to add the rubber boot before connecting.

http://i43.tinypic.com/2dqk5sj.jpg http://i44.tinypic.com/344cpqg.jpg http://i42.tinypic.com/2qdzvr9.jpg http://i39.tinypic.com/a0z0aa.jpg http://i44.tinypic.com/k9bf9.jpg

11) Test the headlights.
Success!!! And way brighter than before!!
http://i40.tinypic.com/2gxgsid.jpg

12) Secure the relay housing.
This was another detail no one mentions when they say this is a 15 mins. job.
There was no room to put it anywhere.
The one screw that was available was too high, and the hood would have hit the relays when closed,
I saw a cavity in the fender, but do not know if water comes in there.
Where did you screw yours to?
I had no idea where to put it, so I just tucked it away near the fuse box.
I did not screw it onto anything, but it's not going to move much.

I read that the relays can get wet, and there's a right way to install them.
(Upside down? Right side up? I was unable to understand the right way, and of course, no one ever posts a photo)
So, I just bagged the relays in saran wrap and rubbed banded it tight, and tucked it up near the fuse box.
Hope that works.

http://i39.tinypic.com/k56f84.jpg

13) Reinstall the headlight retainer ring, grille, and bezels.
http://i43.tinypic.com/2s7ywsh.jpg

Very detailed as always.

Nice write up. Was looking into this the other day.
When you encounter screw/fastener issues, Google/Youtube the solution, there are many out there.
Not sure about the safety/melting/fire hazard regarding the wrapped up relays?
Other than that, thanks for all the work on this.

Yea, I did.

The screw extractors did not work at all.
In the videos, they all use SCREW shaped extractors, not square extractors.
People in the Jeep forum all say the square ones are so great,
but I found them to be totally useless. They didn't even remotely grip the screw.
There was as good as using a wooden dowel!

I was not skilled enough the with dremel to cut the screw head flush enough.
The thin layer that remained was enough to keep holding in retainer ring.

And drilling didn't do anything either. It just made a cavity.
That little headlight screw is basically indestructible!

Nice work mister.

Nice writeup. The original headlamp sockets are difficult to remove from the sealed bulbs because they corrode into the pins. The same will happen with your new sockets and the nice new H4 bulbs. You should look into a product like Gardner Bender Ox-Gard or Ideal NOALOX: Stuff is a conductive grease suitable for putting directly on contacts like that. You'll find it in the electrical section at Home Depot, Lowe's, etc. It's used for mating aluminum and copper conductors, and works great at preventing corrosion in an automotive application too. As I said it is conductive, though, so don't make a mess with it. Some on the blades of the H4 bulb is good enough.

For reference, the spiral screw extractors are designed to be set into a hole in the stuck fastener, then turned in the opposite direction. Using them in a drill is just going to make a mess.

THUNDERBIRDS ARE GO

Just thought this should be saved, good sig also lol

Good job man!! And nice to see you bought decent tools (square bit set)...

if you have the ability to complete this task you should easily be able to use that bit set successfully, a "professional" mechanic would not only laugh, but probably take advantage of the situation...

EDIT: maybe use a pair of needle-nose behind the screw holding and bracing it while you use a bit same size as screw, the 'cavity' you made will break it down and or allow the larger bit size to chase afterward...

go for it!!

Daze,
I am going to buy a set of real screw extractors, and see if I can get them to work with a drill. If that also fails, I will buy a new set of drill bits, and try to just drill the damn screw out and replace with a nut/bolt.

What exactly is the reason for the terribly dim stocks headlights?

1) Did the brightness degrade over time?
Is it the connection prongs oxidize and block voltage?
But, I've had older cars that didn't have such dim headlights.
Were new XJ's a lot brighter, or were they also weak from the start?

2) Are the OEM headlights just a low watt rating?
(What wattage are the OEM lights?)

3) Is the wiring harness known to be faulty? Can't carry a lot of current?

4) Or a inherent electrical design flaw? I am wondering about the design of the original circuit. The advantage of this new relay design is a direct 12-14V feed to the battery, with the headlight switch just acting as a trigger to close the new battery->headlight circuit. But, with the original design, isn't that also, in the end, connected to the battery? Battery->headlight switch->headlights. So what was limiting the OEM circuit from delivering the same 12V-14V to the lights? In the end, both designs have a closed circuit with the battery and headlights, right? In the OEM design, does the headlight switch act as some sort of bottleneck? Was current or voltage being lost somewhere? (If you know this answer, please assume minimal electrical knowledge)

All I did was switch out the stockers for Sylvania Silverstars and it was like a night and day difference. :cool2:

Did this as well, and then upgraded the harness and noticed another significant jump in output. Well worth it, in my opinion.

They got even brighter, seems to me that'll just burn out the bulbs faster.

Yes to all of the above. I dumped this into another thread:

The OE bulbs are something like 35/55 watts and sealed beams have a pretty poor dispersion pattern. Compare to modern vehicles with 80 watt or higher and a much better pattern.

Everything that is build and sold is made using minimum standards,take for instance the electrical system in your house the electrical code (NEC)rules, they are minimum standard,you can always improve it but that costs money.And that is the bottom line,Chrysler could used thicker wires and better materials,but that would cut into their profit margin.The water you drink is treated using minimum standards set by the EPA.
I used to work at FELPRO we did test all the materials that were used on gaskets,guest which one we used.
https://drive.google.com/file/d/0B2C...it?usp=sharing
This is how I did my relays,Electric Fan,Lights and Fog lights.There is room under the hood.You did a good job installing your lights,but did a hack job with the relay.A good set of screw extractors won't help you with that screw,just drill it out.

I just replaced my header/grille that came with some halogens from the JY and though I haven't driven it at night yet,I could immediately tell the difference in illumination...

I will clean and grease all components for now, I know a lot of people are upgrading their harness but after further thought I'm not sure how just how much of an upgrade this truly is as you're still using all the old wiring with a relay...

See my post on the previous page. Only enough current goes through the stock wiring to trigger the relay. This is 300-500 mA compared to 5000-10000 mA.

Read this if you want more convincing. At this point in any XJ's life running power through the stock harness should be considered a safety risk. https://www.cherokeeforum.com/f2/hea...-worth-112584/

By using the harness you are improving the the wires to the lights with a thicker gauge,and using the oem wiring to energized the relay.

understood but you're still using the same old wiring that has been heated and was substandard in the first place... just sayin

I understand what you are saying,But like Salad said the current on the oem wiring is minimal.

Substandard for running a full load. Continued heat cycling leads to failure. A relay is nowhere near enough to break it lol

http://www.swapmeetdave.com/Humor/Wo...mber-Car-A.jpg The load was to big for the car,same thing with the OEM wires to big a load and they will fail.

that twine appears to be substandard but sure does hold up well :)

Salad,
It might be my lack of basic electrical knowledge, but I am still missing something as to how the 2 circuits are truly separate. The headlight switch circuit still powers the old headlight socket, which powers the new headlight sockets/harness. So, aren't they still connected? Whatever maximum amount of current that used to go through the headlight switch and crappy old wires still does, no? B/c we have not changed the old wiring at all. All we've done is to piggyback off the old wiring. So, if all the current is provided from the old wiring to the new wiring, doesn't the same amount of current still go through the old wiring and the headlight switch? I don't see how LESS current is going through the headlight switch, b/c all we've done is add something to the existing wiring. We have not modified the old wiring in any way. We've just "spliced" a new wiring harness directly onto the old one, via the headlight socket. Whatever was powering the old wiring is still powering the old wiring in the same way when the headlight switch is now closed.

prcherokee, nice work, but my engine bay is not like this. In that spot, I have a horn device, and additional wiring that was getting in the way. I will take another detailed photo so you can see.

The switch is no longer connected to the headlights, it's connected to the relay. The relay supplies the electricity to your headlights when you tell it to by pulling the headlight switch.

I see now you got the cruise control servo,you may have room in from of it or behind the battery.

This will explain it better than I can http://electronics.howstuffworks.com/relay1.htm

to reiterate a little more clearly from my earlier post, albeit an upgrade no doubt its just adding a relay and extending the run.. same and or better would be to add a relay in a shorter run to switch eliminating (most) of the old wire with a heavier gauge and longer run to headlights..

just a relay and heavier gauge from radio shack.. Then again someone (like myself) could/would easily start replacing wire everywhere once that far thru the loom.. just because you're already there, turning the project into complete overhaul mode :)

Look for Diesel Daze's XJ on CL in a few months "used to run fine but won't start" :lol:

Salad is right, the wiring was substandard for the load placed on it by the lighting system but it's downright overkill to trigger the relay.

Wait... This is clearer than your earlier post? I must go back and find your earlier post because that would have to be astonishingly unclear to top this.

how'd you know I was having starting issues, I haven't made a thread yet :)

probably is, slept very little last night and here I am again at 3:55am with 2 hrs sleep and feel inclined to answer.. but rather then talk in circles I'll digress until well, whenever.....

Hopefully the net will tire me out to get some sleep, so I can get back on here later and spill some more nonsense... :D

Hello, its me again... yes I'm still awake and a light bulb just went off, or I'm completely losing it from sleep deprivation...

Tell me if I've finally wrapped my mind around this, for some reason I was thinking there was still a load at the switch even with a relay, thus the reason I wanted to shorten the run closer to the switch.. But now that I'm delirious and realize this is the exact job the relay does... acts as a 'bridge' to power the headlights significantly and in turn now the headlight switch only acts to power the relay on instead of pushing more juice through the shoddy OEM wire...

Not sure where I was before but I think I have a grasp on it, or maybe not...

Here is my understanding.

Circuit#1
The headlight switch is connected to the old headlight socket.
The new harness plugs into the old headlight socket
This new harness is connected to the relay.

Circuit #2
A separate circuit #2 connects the battery and the 2 new headlight sockets.

Relay
Circuit #1 and #2 do not touch each other.
Both circuits pass through the relay, but do not actually touch.
The relay switch for circuit #2 is magnetically closed (headlights go on) when current flows through circuit #1 (headlight switch is closed)

My only confusion is that somewhere in circuit #1, isn't it connected to the battery, since the old circuit used to power the headlights? We have not removed that connection. So doesn't the same amount of current go through the headlight switch still? Or is current determined by what is drawing power from the circuit. Headlights themselves are no longer on circuit #1, so it that why there is less current flowing through circuit #1?
(ie: Is current supplied at a fixed rate, or does it depend on what is drawing the current (headlights)

https://encrypted-tbn2.gstatic.com/i...sCSq_XWyLS4ffN
As you can see the White and Yellow wires are connected to the battery,two circuits (two loads).
The green wire from the switch goes to the relay coil (86) the other side of the coil goes to ground (85).
When you flip the switch on voltage goes from the battery to the coil (White wire)or OEM the coil energizes and closes the normally open contact on the relay.When the contacts is close the lights turn on because now voltage is applied to the lights (Yellow wire)and the red wire to the lights.
As you can see the white wire is protected with a 3 amp fuse (smaller current draw)and the yellow wire is protected with a 25 amp fuse (bigger load).
This illustration is a similarity of your headlight switch not an exact duplication,but same concept.By the way the switch is lighted that's why is grounded.
As you can see two different circuits one for the relay and the other for the lights.

http://www.enginebasics.com/Engine%2...ive-relay3.jpg
This is how a relay looks.

here's where I put my relays

That is exactly where I put mine as well.

LOL... sorry to stir the pot.......

I obviously missed this post or would have never responded reading this....
some are probably thinking I've stirred bimmers thread on purpose, I assure you I didn't.....

seriously :)