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Installed HD headlight harness now headlights stay on until ignition is turned off

So, if I just cut that wire and don't connect it to anything will that cause the fogs to stay on anytime both switches are on and disregard the high beams being active?
 
The wire I am referencing in is connected to the harness under the dash and the relay is behind the climate controls; at least on my '98 when I installed the harness.
If you can find that tie in to the harness; then yes that should allow the foglights to stay on even though the hi beams are switched on.
 
CharlesS said:
The wire I am referencing in is connected to the harness under the dash and the relay is behind the climate controls; at least on my '98 when I installed the harness.
If you can find that tie in to the harness; then yes that should allow the foglights to stay on even though the hi beams are switched on.
Click to expand...

Ugh, They should have done this right from the factory.
 
sure you don't have a DRL module?
2009-10-29_224725_drl.gif
 
Devilfrog said:
sure you don't have a DRL module?
2009-10-29_224725_drl.gif
Click to expand...

99% sure that I don't but I can look again. I've actually never seen an XJ with DRL's here in the US.

The lights have never stayed on with the key before the harness.

If I turn the key on without the headlights they don't come on. If I turn the headlights on and then back off with the switch the low beams stay on until I turn the key off or flash the high beams.
 
UPDATE:

cruiser54 said:
Ever see this?

Courtesy of EZEARL
　
Suppose to be the fix:

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?
Click to expand...

This fixed the lack of fog lights and the high beams sticking on. Sweet.

cruiser54 said:
I think it may fix the low beam issue as well. Try it, Mr Guinea pig.
Click to expand...

However, it did not fix the low beams staying on after I've cut the headlight switch off but that's not a big deal. What's strange to me is that it only does it with the engine RUNNING. With the key on but the engine off it works correctly. With the engine/key off it works correctly. I don't understand why. The engine shouldn't have anything to do with the headlight circuit.

Devilfrog said:
sure you don't have a DRL module?
2009-10-29_224725_drl.gif
Click to expand...

I do not have DRLs. I do have the headlight sentinel feature.
 
cruiser54 said:
Ever see this?



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?
Click to expand...
Here is my description on the fog lamp system on the XJ.

scoobyxj said:
Factory Foglights and your LED lights. Your issues is how the factory designed the system. The fog relays coil is grounded through the drivers side high beam lamp filament. (This is also why that when the drivers side high beam burns out you loose your fog lamps) How it works is when the lights are off you have no voltage to the high beam and you basically have continuity to ground through the lamp filament. When the high beams are on you have voltage on both sides of the relay coil (which causes it to denergize) turning off the fog lamps.

The fix....
There are two ways you can do it. The last one being the most legal.
1.. Find and ground the red trigger lead from the fog lamp relay.
This will allow your fog lamps to operate regardless of the high or low beam as long as the parking lamp are on.

2..Again using the red trigger wire from the relay.
Use a additional relay to ground the OEM trigger wire when the high beams are on.
(30 to the trigger wire 87 to ground 86 to ground, and 85 to the red positive wire for the high beams.)

Now you can find the red trigger wire behind the drivers side head light, but the high beam + wire is also red as well. However if you pull out you air cleaner you will find the front lighting harness plug. On the body side of the plug that trigger wire is Brown with a White tracer while the high beam lamp feed continues in red. So if you locate and cut the wire there you can use the front end harness side as your new trigger wire, and ground the body side wire.
Click to expand...

I have the same issue (lights staying on 'till you turn off the ignition). I always put the blame on the sentential module being bad (I did a harness in the process of making it road ready so I never knew if it acted that way before, or not.). Give me a few days and I'll do some digging and some probing, and see what if anything I can come up with. I'm really leaning towards the fog lamp system having something to do with it because this one has fogs (1999), and my old jeep (2000) didn't (I didn't have the issue on the other one.).
 
Last edited:
So, if I understand that correctly I should be able to permanently ground the fog lamp wire in question and the fog lamps would stay on anytime I have the headlights on (high or low) correct?
 
Did this ever get resolved? I have an LMC truck harness and my headlights will not turn off while the engine is running unless I flash the high beams.
 
Do you have foglights and what year?
 
Have you tried unplugging the DRL module ... If you have one that is ... Seen several go out and make the headlights stay on.
 
Daytime Running Lights ... They have a tendency to keep the headlights on when the go out.

But it seems it was more a Canadian thing to have them (federally mandated up here since 1990).
 
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