Headlights Staying On W/ Ignition Off

Hi Yall! I've recently been having an issue with my low beam headlights constantly staying on even with the truck off, and I am at a bit of a loss as to what the problem is.

Preface: I got back from a trip where my truck (2003 Tundra AC) was sitting in a parking lot for 10 days, and when I went to start it the battery was dead. After jumping, I noticed the low beams were on, even though the headlight switch was off. the lights have been staying on, regardless of what position the combination switch is in and whether the truck is on or off. (my truck does NOT have DRL's)

I replaced the combo switch initially thinking that was the issue, but that did not solve the problem. Everything else related to the switch, including the fog lights, turn signals, high beams and dash lights work normally.

When I unplug the switch, the low beams do turn off, but the high beam indicator on my dash turns on and stays on even with the truck off.

when I plug the combo switch back in with the truck off, the headlight relay clicks and the low beams immediately turn on again, and the high beam indicator turns off. If I unplug the relay, the low beams will also turn off along with the high beam indicator, and plugging the relay back in immediately causes them to turn on again.

Curiously, if I turn the high beams on with the combination switch and the truck off, the low beams turn off and the high beam indicator turns back on, but the high beams themselves don't turn on.

I'm not very experienced with car electronics, and was hoping someone could help me out with diagnosing what might be wrong. I've done some poking around with a multimeter, and thus far have tested resistance on all the grounds for the combo switch and gauge cluster (all of which were good). I also tested the red/grn wire for the high beam indicator from both the combo switch plug and the gauge cluster plug and noticed it is getting 12v when the truck is off. That's as far as I've gotten so far. I included the wiring diagram i found online and have been referencing. Any help would be greatly appreciated, thanks!

 

Sounds suspiciously like a short in the system. Do you see anywhere where there might be water infiltration? When was the last time the windshield was replaced? There are threads on here about water getting into the interior fuse panel and wreaking havoc on electrical systems.

 

This exactly. Water getting in the fusebox in the driver side lower dash will cause similar issues.
https://www.tundras.com/threads/02-tundra-electrical-problems.45605/#post-1174202

 

How old is the battery? I have experienced similar symptoms with the headlights or parking lights staying on when the battery was going bad. The issue was the battery. New battery, no more problems.

 

The windshield hasn't been replaced since I've owned the truck (2ish years). The battery was replaced in October, so it shouldn't be that. I was coming across some other forums of people having issues with headlights staying on which was ultimately caused by a failing integration relay. There's no signs of water intrusion near that fuse box/relay but it's possible. What would be the best way to test that the relay is working?

 

I don't think you're going to see it by a simple visual inspection on the front side. I think you need to remove it and check the back and where the harness plugs into it.

 

Doesn't matter if it has or hasn't been replaced. Water will enter thru the a-pillar at the windshield trim where it's fastened, or it'll enter from natural separation of the windshield especially in rust belt/wet climates, or it'll enter via the driver door seal.

But if it's only impacting one circuit, the symptoms don't necessarily fit. And before you go through the pain of pulling the fusebox...

I believe (don't quote me here) the factory RS3200 TVIPS security/keyless system in your truck is setup is what controls the headlight function when the truck is OFF/locked, and that function can be programmed to a degree. But in general, the system is supposed to turn the headlights off when two conditions are met:

1. The truck is OFF
2. The driver door gets opened at least ONCE after the key is OFF

That's assuming the the door open/close switch is working correctly, thus the truck knows when you open the door - have you noticed any other lights staying on, dome, courtesy?

That's also assuming something isn't impacting the circuit, like ... did you or a previous owner install LED headlights? (I'm not sure if the differing resistance ... maybe if LED resistance is lower, the truck things the lights are already off?)

That's lastly assuming you're using the original factory alarm, and someone hasn't hacked in another alarm over the years, whether it's still primary or not.

Do you have the standard 2003+ OEM keyfob (pic below), or is it some weird aftermarket shit?

Look under your dash. Do you see any weird black boxes zip-tied up, any evidence of spliced wires?

Let us know ....

​

 

Nothing else stays on after opening the door, and the door switches aren’t sticky or anything, so I think those are working fine. There was an aftermarket alarm system installed in the truck when I bought it unfortunately, but I completely removed it immediately after I bought it and haven’t had any electrical issues until now. I removed and cleaned up all the splices between the factory wires and the old aftermarket alarm wiring, but it’s possible one of those old splices might be causing some short/issue? I don’t have a key fob for my truck, I just use the key to lock and unlock it. As far as the windshield goes, I was just answering someone else’s question, it’s entirely possible it’s leaking onto the fuse box/integration relay but I just wanna figure out a way to test that before pulling it out ideally.

 

Head scratcher indeed, especially the below....

If you followed the link @NickB_01TRD posted above, you'll see that Toyota calls the interior fuse box and the back side the "Driver Side J/B and Integration Relay"

Just head scratcher comment....when you had the combo switch and gauge cluster(Combination Meter) unplugged, that should eliminate anything doing with TVIP alarm system.....should.

Good test....if you don't mind doing that again and with combo switch and Combination Meter unplugged, then unplug both LH and RH head lights. With your volt ohm meter set to ohms(continuity test), I'd like to know if any of those conductors are showing a short to ground. Semi simple test instead of the Integration Relay removal just yet....pain in the ass but doable.

Place meter lead to a ground(GND) close to either LH or RH head light plugs.

LH side....one lead to good GND and other lead to LH plug Red/Yel pin 2.....short to ground ?
one lead to good GND and other lead to LH plug Red/Grn pin 1....short to ground ?

RH side....one lead to good GND and other lead to LH plug Red/Yel pin 2.....short to ground ?
one lead to good GND and other lead to LH plug Red/Grn pin 1....short to ground ?

 

Thank you! I’ll do those tests tmrw hopefully and see what the results are.

 

@BubbaW Sorry for the delayed response, it's been a busy week. Here's what I have:

With the combo switch and meter unplugged and my multimeter set to ohms on the setting where it will beep, both pin 2 (Red/Yel) and pin 1 (Red/Grn) show no short to ground on both headlight plugs. When the combo switch is plugged in however, pin 1 (Red/Grn) will cause the voltmeter to beep (short to ground?) on both headlight plugs.

 

Head scratcher indeed

Fixing to be heading to church but have couple quick thoughts about the below quote.....

When time permits, remove the head light relay in engine bay for bench test and note from pic below the pins 3 and 5 location(H-LP relay contacts). Would like to see if their is any continuity between 3 and 5 on the bench suggesting welded/dirty contacts or such. While relay is out, check the relay socket for voltage with key out of IGN, combo switch in normal off position....with neg lead of meter to relay socket pin 2 and pos lead to relay socket pin 1, any voltage ?



Agree with what others have mentioned, not only is the Integration Relay/Fuse box a suspect, I personally feel there's at least another gremlin. Want to eliminate a possible bad relay with above request.

Perhaps others see something I don't !

Good Luck

 

Any update? I have the exact same problem. No moisture in the area that I can tell... I suspect the integration relay, if it were a customer I'd just say replace that but I'm a cheap mechanic and don't want to just slap in a 100 dollar eBay replacement.

 

It went away a couple weeks after I posted this forum and I wasn’t able to diagnose it further unfortunately. But from what I was able to gather is that it’s either the integration relay or a short somewhere in the wiring “before” the relay/fuses in the engine bay fuse box if that makes sense. But due to the irregularity of the problem my guess is it’s probably the integration relay, that’s what I’m gonna replace if it ever comes back.

 

Well, we had yet another, albeit new case of electrical gremlins related to water coming down the wiring upstream from the integration relay/fusebox: https://www.tundras.com/threads/electrical-problems.156818/

All too common. Anyone not checking these areas, even if they’re “dry” would be doing themselves a huge ass disservice.

 

Again I don't think this particular issue is moisture. Literally exactly the same with multi purpose switch disconnected and hi signal showing.