First post! This forum has basically made owning an XJ possible for me. Amazing resource.

My problem: When I installed the Putco headlight harness on my 1998 Sport, it seems to have disabled the daytime running lights (low-voltage low beams). The lights function normally otherwise; the amber DRLs turn on at the first click of the light switch, then the normal low beams come on, and the high beams work. How do I troubleshoot this?

Install notes: I grounded to clean grounds (passenger side to the body ground for the battery, drivers side to a radiator bolt--was going to run wire from DS to the battery ground as well). I did not install a fuse between the power supply and the harness. I wired the harness to the power supply to the fuse box, as per here, instead of the positive terminal on the battery.

I'd like to keep the DRL, since they're required by law, and turning on the low beams dims turns on the dash lights.

 

Here ya go:

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?

 

My high beams work fine, I don't have the factory fog lamps. Is the principle the same? Ie, since the putco harness bypasses the switch, the DRL relay doesn't receive sufficient current to activate and the lights stay off until the switch is engaged? Where would I have to splice get current to the relay?

Sorry, electrical is really at my limit of understanding..

 

After almost a year, I put in the day to figure it out myself. To get DRLs to work on a 1998 xj (and I'm guessing 97-01) with a Putco harness, you need to splice in the red wire from pin 1 of the DRL module (high beam output) past the high beam relay into the two blue wires going to the headlight sockets.




I can't believe how ridiculously long it took me to figure this out

I mistakenly tapped into the low beam wires.. I might care enough at some point to switch them. We'll see.

 

Interesting, I had a similar problem with my DLRLs but they would come on dim and the relay would buzz My solution was to just turn on the headlights while I drove. Unfortunately I have 2 vehicles, and I would often forget to turn on the headlights in the Jeep. Now the DLRLs don't work at all. I am guessing that I burnt out the relay for the DLRL

 

Wish I'd seen this thread before. I just disabled the DRLs (were tripping the Putco's relay) and drove around with my low beams on.

I don't mind the dash light thing as DRLs don't illuminate the tail lights.

 

I got tired of having to explain to friends why clock wasn't visible.. and the prospect of having to change the dash lights before their time didn't appeal to me.

DEFINITELY send the power to the high beams. Otherwise, the low beams trip the high beam dash indicator, and seem to cause some weird artifacts (flickering dash, pissed off battery voltage gauge..).

 

I am jumping in on this old post as I am trying to figure this DRL - headlight wiring harness problem. I had the same buzzing when I first installed my headlight harness upgrade. That lead to burning out the DRL module. I replaced the DRL module and the buzzing returned. Eventually I just unplugged the module.
Before I start cutting wires I wanted to clarify from post #4. The red wire out from the DRL module is completely cut and spliced into the high beams after the relay or is the red wire spliced (the red wire connection is maintained to the juction block).
It seems to me if the connection is not cut the DRL will still send power to the relay which is what I am trying to avoid.
In the wiring diagram it looks like the junction block contains fuses that would be bypassed also by splicing into the harness wiring. I am guessing the I want to ensure that the harness fuse is not also bypassed.
I guess what I am asking is , Is the junction block on the wiring diagram still relevant if I am running the upgraded wiring harness?

Thanks,

 

Hi,
I too have this issue, Just installed the harness after it sitting in a box for a year and found it was all fine until I started the truck and started moving. That's when the DRL kicked in and the annoying buzz was being generated from the one of the two relays in the kit (or boths). I tested it before driving and all was well. When I turn on the headlights it stops and all is well. Also goes away if I put High beams on. I disconnected the new harness (but left it inside the jeep) for now as I don't want to kill the DRL relay. Until I'm certain of a cure.

My Jeep is a 1998 XJ with no fog light (nor their harnesses) but has a fog light switch inside if that matters.

I'm running the H4 PIAA bulbs in IPF housings.

PLEASE HELP! Cherokee-One (or many) Canobe I'm mechanically inclined and work on this think all he time. As for electric aspect I'm not that good. If there was a diagram It would help me and others on what to do /splice... I went cross eyed reading about the wire above and what to do.

Thank you

Rob.

 

I am in the same boat. Canadian XJ. Dumb question, but for the splicing of the #1 wire from the DRL module, would the plug still be plugged into the module and just splice behind the connector, or would you remove the plug out of the module and then splice? I left a visitor message for jpatrick but it looks like he hasn't been on the forum in years. Thanks!

 

My most famous post on the internet 😅

I unfortunately can't remember. I think I spliced after the plug but can't be sure, I don't have the jeep anymore, sadly. I do recall that my post outlining where to splice for DRLs was clear enough, so I'd just read it carefully with the wiring diagram in hand. Just remember you're trying to get the low voltage DRL current from the module to the highbeam, past the relay (since the DRL stops sending current when you turn the lights on). Hope that helps, good luck!

 

Awesome thanks man for responding!