This one? https://www.ebay.com/itm/Ceramic-H4-...19.m1438.l2649

 

that's a little expensive. There is a member here that sells harnesses for $18...I bought it a year ago and have had no problems.

 

^ That's right. jhc7399

You should be able to find one for $20 or less.

 

Sorry to hijack this thread but I installed the harness and have the stock fogs. I have the problem that my high beams stay on and have to turn off the lights then turn them on to get back to low beams. I know I saw something in this forum about splicing a wire into it to avoid this problem. I've been searching for it but can't find it. I've got a 2001 60th Anniversary model.

Can someone direct me to it?

 

Never mind the above post. As soon as I posted it I looked back to page 36, 37 and found the answer.

Thanks Cruiser54

 

Courtesy of EZEARL




Suppose to be the fix:
If you have stock fog lights on a 97+ and upgrade your harness in a manner that uses the factory wiring to trigger some new relays, your fog lights will have and/or cause issues unless you make some additional modifications to address the problem. It doesn't matter if you use a plug and play harness like the eautoworks or if you split your harness open and completely strip out all the extra factory wiring like I did. The factory fog circuit will cause your new lighting system to not work properly.

If you do nothing, your headlights will work as mentioned above. Low beams will be fine, but after you turn on your high beams, they will not turn off again until you completely turn off your headlights. Big issue here is that when you switch back to low beams, both the high beam and low beam filament will be remain powered causing your bulbs to endure 115W worth of heat output instead of the 55W or 60W that they are designed for. From what I've read this can cause them to overheat and burn out within minutes.

So what is happening? If you look at the driver's side headlight plug (and you have factory fogs) you will notice there are two red wires coming out of one of the terminals. One is a small 18g Red wire which sadly is the stock high beam wire. The other is an even smaller 20g Red wire which ties into Fog Lamp Relay #1 in the PDC. Please keep in mind that Fog Lamp Relay #1 is NOT used to provide battery power to the fog lights the way we commonly use them with aftermarket lighting. It is located before the switch and simply cuts power to the Fog Light Switch unless the Headlight Switch and Beam Selector Switch are in the proper positions. It does this as law dictates that you can't run your high beams and fogs at the same time. Though not a problem here in CA, I've read that states with safety inspection programs will fail your vehicle if the lights don't operate this way.

I dug into the wiring diagrams but had to have kastein help me decipher them because there was something about this circuit that just wasn't making much sense to me. I still don't understand the function of Fog Lamp Relay #1 in its entirety, but we're only concerned with the part that is affected by the headlight harness anyways. Essentially, when your Headlight Switch is off, the relay coil receives no power and therefore won't allow your fog lights to come on. When your Headlight Switch is turned on, one side of the relay's coil receives 12V which causes the relay to activate and send power through to your Fog Light Switch. When you turn your high beams on, 12V is sent out to your headlight socket via the Beam Selector Switch, and then is sent back to the other side of the relay coil via the skinny Red wire on that shared terminal. This brings both sides of the relay coil to 12V, thus causing it to deactivate and turn off the Fog Light Switch. Weird huh? The factory designed it so that the relay is off with both sides at 0V, on with one side at 12V, and then off again with both sides at 12V. While it makes perfect sense now, this is the part that was confusing me.

So what's the problem then? Well, it turns out that even when the high beams are off, there is still approximately 5V on that skinny Red trigger wire for some reason which I still don't understand. While this is obviously not a problem in the factory configuration, it becomes a problem when you are using the high beam wire (which is directly tied into the skinny Red wire) to trigger your aftermarket high beam relay. A typical automotive relay requires approximately 8V to activate and needs to drop to somewhere below 1-5V to deactivate. When you first turn on your lights there is no problem because the phantom 5V is not enough to activate your new high beam relay. When you turn your high beams on, your new relay gets 12V and kicks on. When you go to turn off your high beams, the phantom 5V keeps the new relay from deactivating and voilà, your high beams are stuck on...

So how do we fix this? There are a few common suggestions that are out there that I just wasn't happy with, and a few that sort of work, but not as required by law:

1. Don't use your high beams, new lights are bright enough anyways (OK...)
2. If you have to use your high beams, turn your headlights off briefly to get them turn off (PITA)
3. Pull various fuses (lose your fog lights)
4. Pull the fog lamp relay (again, lose your fog lights)
5. Modify the fog lamp relay (fog lights work, but won't cut out when your high beams are on?)
6. Install a jumper in place of the fog light relay (fog lights work, but switch is always hot?)

One post I saw got it right though. lilredxj99 mentioned it in another thread which I didn't find until after the fact. The details were a little fuzzy and I still thought the issue deserved some further explanation so that's why I just wrote this damn novel...

Oh yeah, so the right way to do it... Cut the 20g Red Fog Lamp Relay #1 ground/trigger wire at the back of the driver's side headlight plug. Extend this wire using your preferred method so that it is long enough to reach your new aftermarket high beam relay. Splice it into the 87 pin (output) of your new high beam relay. If you have two 87's (which is ideal), either one is OK. Do not however use 87a if your relay has it!

Yep, that's it... Your high beams will now turn off when they're supposed to, your fog lights will turn on/off when they're supposed to, and your low beams will continue to work as they're supposed to. Sure you could have skipped all the way down to the bottom and found your answer, but you wanted to know how/why it works, right?

 

And thanks EZEARL for the extensive and informative write up!

 

I can't take credit for devising the fix. I came across that years ago when researching a harness upgrade for my '96. I don't have fog lights so ignored it. But when the problem with the fog lights started showing up here I tracked down that info and posted it. Took a long time to find it but I got lucky I guess.

 

Hey guys,

Just got a 1990 Cherokee XJ working on getting it road ready. Found that I have the same dim HL issue that everybody else has. I've decided to build my harness, mainly because I have done this same upgrade on
a 1962 C10 I had. I kept the stock headlights and there was a huge improvement. This time I have ordered the Genssi H4 Conversion lens kit off Amazon along with a set of Hella H4 60/55W bulbs.
Anybody use this lens kit? How were your results?

Thanks!

 

First chance you get, go to www.cruiser54.com and do Tips 1,3,4, and 5.

 

Does anybody sell a replacement/upgraded headlight harness that includes new turn signal sockets?

 

Thanks Cruiser54. Your site was one of the first sources of info I found when researching the XJ's. Thanks for maintaining this for everyone's use.
I will start on these tips asap.

Thanks

 

Nope. 2 different systems.

 

Keep us in the loop and if you have any questions, post them up.

 

So after upgrading to the new wiring harness with relays it should be capable of handling higher wattage bulbs. I currently have the stock 55/60 watt low/high beam bulbs in place. Can 80/100 be safely used without frying the electrics? I would assume so since now the power is not being sent thru the switch and the relays are responsible for turning the lights on and off that higher wattage bulbs could safely be used.