2000 XJ with after market head lights and a security system.
Came home one night to find my XJ off in my driveway with its brights on. Turned the lights on and off and the high beams were still on.
So far Ive tried a new Multifunction switch and checking relays but non of that did anything.

Any ideas out there that might cause this? Im also not sure which fuse runs the high beams. None of them specify high .

 

My bet is it’s in the security system itself or where the security system taps the wiring harness somewhere. A rouge 12v is getting into both left and right headlight and they are on separate circuits outside the switch.

 

Aftermarket security system? Quite likely the problem - but only if triggering the alarm flashes the hi beams, otherwise don't see how/where there's any connection (ouch!)

Aftermarket headlights LED? If so, even more likely to be the cause..

Combination of the 2 is a guaranteed recipe for disaster!

 

Here's a diagram for a 2000 XJ. According to this for both lights to be on it must be between the switch and the fuse block. In my experience with dealer installed security and keyless entry when I worked for Ford most systems tap the master harness under the dash on the driver's side. Since the fuse blocks are on the passenger side in this vehicle this means it's a likely culprit. But with this he can trace violet white and red orange from the switch to the fuse block. He can also verify this by removing the fuses.

 

Update.
I disconnedted the security system but nothing happened.
I traced the Multifunction switch wires and they go over the steering wheel column, across the knee pannel and then back to the right to the passenger side. The secuity system isn't tied into these wires.
Tried a new Multifunction swithc, nothing. Lights are still on when the MFS is unplugged.
Pulling the MFS toggle makes my light brighter. This tells me my light might be turning on because of the constant 7 something volts that are sent to the headlights.
I have a light delay feature but ran out of time trying to find it.
Pulling fuse 16 in the PDC killed both lights
Pulling fuse 3 in the Junction box killed the driver light (You can see fuse 3 in the diagram above)
I pulled all the fuses in the JB and the right light never went off. Ive pulled all the relay in the JB and PDC, nothing.
I learned about a day running light box but I could never find one on the passenger fender or driver fender where some forums said to look.
I pull each head light and the wiring looks pretty stock. The lights came with the jeep so Im assuming they are LED because they freeze up in the snow. (No heater block on the housing)

This all just started the other night. Ive had the jeep for 2 years and never had this issue before.

 

That's it's only just happened is a twist I wasn't expecting.

I thought only Canadian XJ's had DRL's but, in any event don't they utilize the front turn signals?.

Can you post a picture of a headlight, so we can see whether they are LED's. Have to say, they're still my prime suspect - but let's not be too hasty.

Do you know if the security system is OEM or after market?

 

If you are pulling Fuse 16 and both lights went off that means that your problem is between the C1 connector in the fuse block and the right headlamp. You can see in the diagram that the headlight are still wired together till it makes it to C4 at the junction block. This is why you are getting the left headlight only to turn out when you pull fuse 3. This is because of the split or splice in the Junction block. Power is being back fed though fuse 3 from that c4 junction block splice. You are either getting a rouge 12V entering the circuit, or a rouge ground has been introduced into the circuit completing the circuit. You're going to need to follow the problem through the Red/Orange wire from the C1 connector at the junction block all the way to the headlight. I would find the c106 connector and with a multimeter see which side has 12v. The black side of the meter must be on a known good ground. From there you can narrow it down upstream or downstream from C106. When looking at the wiring make sure that wires don't have coating worn and showing exposed wires touching other wires (external rouge 12v introducing power where it should be) or bare wire touching metal on the vehicle such as the body (grounding and completing the circuit which is what I ultimately suspect). You could also have melting at a connector creating a mess for you. Hope this helps!

 

Power is power. I don't suspect the LED themselves. He's just checking further down stream from that connector I suggested. But to rule it out he could pull the LED bulb and check to see if he has power at that connector with a multimeter. Guess he could use a test light too. Also if he disconnected the passenger headlight and it were the culprit the drivers headlight would begin to function normally because the thing completing circuit has been removed. Same goes if he disconnects from that upstream connector and the problem is downstream to the towards the headlight. The other light should function normally again. If it't not the light itself it must be a wire or connector. Also some LEDs have DRLs built in. Mine do and my Jeep is not factory equipped with DRL.

 

Update:
Ive unplugged C1 in the Junction Box and Unplugged C106 behind the driver side light so the wire should be free of power. I get 12 volts on Pin 6 of C106 and I get 12 volts on Pin 11 of C1.
So somewhere in the RD/OR wire im getting 12 power. Right?

Also the Fuse 16 I pulled in an earlier post was in the PDC in the engine bay, not the fuse 16 from the Junction box.

 

There is a lighting module and it does not like some LED headlights , Have you tried plugging in a stock headlamp ? To fix the problem if it is the head lamp causing the problem you can ad in a relay kit for the headlights .

 

That's why they would've been my prime suspect but we don't know if the headlights are LED's &, in any event, the problem didn't occur when they were installed but a couple of years later.

Therefore I'm going with the more scientific approach - although I don't pretend to understand the details, so I'm glad it's not me that has to follow the fault finding process.

 

Solved... I think. C1 from the Junction box that supplys power to the lights through C106 might have water behind it in the JB. When I push on C1 or jiggle the wires, the lights will flicker and occasionally go out. Ill have to dry it out. Still doesn't explain why the Red wire in th C1 and C106 had 12volts when everything was unplugged. My guess on this is that there is a raw wire behind the dash. I tried pulling the dash but the wire goes up behind the heater and I didn't want to mess with that.

Back to my water theory, there are 4 plates that direct power to all the different fuses and wires. They are seperated by plates of plastic, but if water gets in there, it can connect the different plates which can cause things to power up. I had this happen two years ago with my rear defrost circuit. It got so bad that my key wouldn't shut the jeep off. I had to push the defrost button to kill the motor. Pulled the JB and let it dry out and then sealed it. Worked like a champ until now. Water must be getting in through the plug. Previous owner punched a big ol hole in fender right above the JB to run AUX wires. Ive tried to seal it but it must be failing.

 

I agree you shouldn't be having power on that line regardless. I'd deal with one problem at a time. It is possible you could be drealing with two problems at once. We know water isn't supposed to be in the junction block. We also know if water is there it can also be going elsewhere behind the dash. Sounds like you've got your hands full. But get rid of that conductor that's not supposed to be there first (water). Then I'd circle back to that hot wire. And sometimes we don't wanna take things apart but we have to. Called wrenching and comes with the turf.