2002 Tundra Headlight Issue...randomly comming on

So, I'm the original owner of my 2002 Tundra and for the past 10 plus years the headlights will just come on for no reason. This could happen anytime that the truck is off. Once the lights come on they will stay on till the battery is dead. I may go months without them turning on or days...never the same.

I've had the truck at the Toyota dealership sitting for two weeks and they could not find any electrical issues that were causing this to happen. After that I took it to an independent mechanic and he too could find no issues.

So, has anyone else had this problem or know of a solution? Any suggestions are appreciated.

Thanks in advance, Chip

 

Need more info.

Which region of the USA did you buy your truck? (NW, NE, SE, NE, Central?)

Is there (or was there ever) a non-factory alarm installed, either by a shop you hired after purchase, or maybe ported at the dealership before you took possession?

Are you running LED lights for any of your exterior lighting - rear and 3rd brake lights, headlights, blinkers, fog lights?

Do you have fog lights on your truck?

Have you ever replaced any relays on your truck, for flashers, etc.?

Something to check: When the headlights stay on, do you notice the dome light in the truck is also on? (asking, could indicate a door pinswitch is bad)

Something else to check: Where is your headlight switch set to on the stalk when this happens, "AUTO" or "OFF"?

 

1) I purchased the truck new in North FL and it has resided here for the past 20 years.
2) No alarm has been installed but there is a keyless entry that was installed by the dealership when I purchased new.
3) No fog lights but I have installed LED lights on my brush bar. However, this problem was happening loooong before the lights were installed. You can see the lights on my "avatar".
4) Never replaced any relays or had any electrical work done, except the radio (see below).
5) No lights inside the truck come on when the headlights are on.
6) I do not have an auto feature on my stalk, only on and off. I have to manually turn on my lights but when I turn off the truck (even if the headlights are still on) then the headlights turn off.
7) The only after market electrical thing I have done to my truck was have a non factory radio installed about 12 years ago. I really cant remember if the problem was happening before I changed out the radio or not.

In the past I have woken up at 3am, after not having driven the truck for days, to find the headlights on...creepy really.

Any suggestions are appreciated

 

Does your truck have daytime running lights?

 

No running lights, unless you call the parking lights (side lights) running lights.

 

I don't have the electrical diagrams in front of me, but I would suspect something is completing the headlight circuit to GND to turn them on.

 

Breakdown on why I asked, and some follow-up questions:

You're in FL - I wanted to get a gauge whether corrosion could be at play. Tell me, do you live within 10 miles of the ocean, do you launch boats in fresh/brackish/salt water ever?

We often find people tapping into the light circuit or installing LED bulbs will cause all kinds of stupid stuff, as will alarms and such.

It sounds like you bought the truck new, that means Gulf State Toyota would've had their hand in it if it had dealer-ported keyless entry. Can you show me a picture of the fob you got from them, the one you currently use? I want to rule out them installing the Securikey+ system, which is a pile of garbage that would absolutely cause this issue.

Am I correct that you keep the lights in "ON" position at all times, knowing the truck will turn them OFF automatically when you exit the vehicle?

My mistake btw. I forgot our trucks don't have "AUTO" on the stalk. Now I look, I see it's OFF - PARK LIGHTS - HEADLIGHTS, and the newer trucks have a spinner mid-stalk for fogs (older trucks have in fog switch in-dash)

I tend to agree, and corrosion or even a faulty relay could 100% cause this problem. So could faulty wiring causing a relay for the headlights to activate when it shouldn't. But it really, honestly stinks of faulty alarm/keyless entry problem to me. I'm thinking Securikey+ is at play, but I'm totally OK (and hope for OP's sake!) I'm wrong on that.

 

Plausible, plus the pos voltage from Batt has to go thru "Head Relay" contacts 1 and 2 to supply Head lights their batt + signal. I also feel you'll agree the circuit w/o DRL is pretty straight forward.

OP mentioned no relay was changed by him and if dealer nor mechanic changed Head relay, the relay could be bad but it would be because of "sticky relay contacts", plausible but not likely.

The Light control switch could be intermittently bad ?

Last but not least, since Integration Relay is part of circuit, corrosion is a possibility, which I assume is one of the roads @Shifty has in mind given the FL comment.

 

Yup. This was next in the line of questions: "Has windshield ever replaced or leaked that you've known?" We've seen it enough, eh? @chip5244 check out THESE PICS

However, I hadn't thought about the actual wiring of the stalk getting pinched and/or shorting out, or the switch having gone bad. That's a good one.

I know a lot of people lights in the ON position because opening the driver side door in many pre-2010 Toyotas makes the headlights automatically shut off. The reason I asked OP about the stalk ON/OFF position is b/c the only thing I can think of which intercepts the light circuit to turn them on/off while the stalk is in OFF position would be a keyless/security system.

If they leave the stalk to ON all the time, I'm going to guess this is actually a problem with something else in the actual circuit or tied to it.

 

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