Electrical gremlins in the dash and headlights - help!

[Weetabix]

I have a '98 4R, 3.4, manual, SR5(?). I bought it about 2 years ago, and I've had this problem about 3 times.

When I first bought it, a few times, the headlights would stay on after the key was out and the headlight switch turned off. My son alerted me to it an hour or so after I'd gotten home. I replaced the headlight relay, and I thought it fixed it.

Last winter in the very cold, it did it again, but this time, the warning lights on the dash started fading in and out, never going fully on. A chime rang weakly as well. Pulled the headlight relay, and the dash continued to act up. Pulled the battery cable to keep from losing a battery. Took it to a shop and they couldn't get it to do the same thing and they couldn't find anything wrong.

Now, it's doing it again. It seems like it's got to be a problem in a switch, relay, or chip somewhere, but I'm not sure where to look.

It seems like it can't just be the headlight relay alone given the antics with the dash lights. I tried jiggering with the key in the ignition, but that didn't stop anything. It's also very irregular. Three times with the headlights and twice with the dash lights in two years.

It's never left the headlights on after the key is out and switch is off then turned them off like newer cars do. Is it possible that it's supposed to have that feature and it's mostly not working? The first time, the headlights stayed on for an hour or so, until I disconnected the battery.

Any thoughts on what to check?

 

[IBallEngineer]

I have a '98 4R, 3.4, manual, SR5(?). I bought it about 2 years ago, and I've had this problem about 3 times.

When I first bought it, a few times, the headlights would stay on after the key was out and the headlight switch turned off. My son alerted me to it an hour or so after I'd gotten home. I replaced the headlight relay, and I thought it fixed it.

Last winter in the very cold, it did it again, but this time, the warning lights on the dash started fading in and out, never going fully on. A chime rang weakly as well. Pulled the headlight relay, and the dash continued to act up. Pulled the battery cable to keep from losing a battery. Took it to a shop and they couldn't get it to do the same thing and they couldn't find anything wrong.

Now, it's doing it again. It seems like it's got to be a problem in a switch, relay, or chip somewhere, but I'm not sure where to look.

It seems like it can't just be the headlight relay alone given the antics with the dash lights. I tried jiggering with the key in the ignition, but that didn't stop anything. It's also very irregular. Three times with the headlights and twice with the dash lights in two years.

It's never left the headlights on after the key is out and switch is off then turned them off like newer cars do. Is it possible that it's supposed to have that feature and it's mostly not working? The first time, the headlights stayed on for an hour or so, until I disconnected the battery.

Any thoughts on what to check?

You are right, it's not the relay. And no your truck does not have the delayed auto off for the headlights. The way it works is there is a micro circuit that turns the headlights off when you turn off the key. My initial guess, and that's all I'm doing at this moment, is that either the Combination Meter micro circuit has failed, or it's not always getting the message that you turned off the key. Now more disturbing is that you said it happens with the headlight switch off, which points to either a stuck relay or a stuck switch circuit. Or of course, a short to ground in the switch circuit. I'm going to have to ask [MENTION=10169]TheDurk[/MENTION] for help on this because he has the earlier EWD, and I don't want to send you on a wild goose chase.

If you want, we can solve it, gremlins are afraid of my face!

:guitar2:

 

[Weetabix]

Oh, I totally want it solved! Gremlins just laugh when they see me coming.

More symptoms for the benefit of the diagnosticians:

- With the key out, the lights stay on, as I said. If you turn the headlight knob to the parking lights, the headlights go off.
- With the key out, the locks actuate themselves one way or the other. So, let's say, I go into a place for a coffee to go. Being too lazy to take the battery terminal off for so short an order, I turn the headlight switch to parking lights so as not to drain the battery. Come back, and the locks are unlocked. This has happened twice. Play with key in, turn on, key off and out, and the locks locked and unlocked a couple times with me in the car as I sat there a bit waiting to see what would happen.
- Once, putting the cable back on, a small unit on the fender well on the passenger side under the hood kept clicking. I haven't looked up what that is yet. It's in about the middle, behind the air filter box.
- Occasionally, the door chime chimes with the door closed.
- Twice, while turning the key to start the car, something under the top left of the dash was buzzing weakly.
- Jimmying with the key in the ignition - in, out, left, right, doesn't seem to change the behavior.

In Alaska, I had a car that the headlights would go out when you were driving at about -40F. I thought it was a contact shrinking. The first time this happened, it was cold for here, say 10F, and this truck doesn't like the cold. Shop couldn't get it to do it there, even after sitting outside all night.

This time, there was heavy rain. A car guy in the office is speculating about a wet connection somewhere grounding or shorting.

I'm wondering a bit about the ignition switch or a bad or wet connection, but I'm not averse to replacing some other parts to see. The problem will be how infrequently it occurs. I'm not sure how I'll know when I've cured it.

 

[IBallEngineer]

Oh, I totally want it solved! Gremlins just laugh when they see me coming.

More symptoms for the benefit of the diagnosticians:

- With the key out, the lights stay on, as I said. If you turn the headlight knob to the parking lights, the headlights go off.
- With the key out, the locks actuate themselves one way or the other. So, let's say, I go into a place for a coffee to go. Being too lazy to take the battery terminal off for so short an order, I turn the headlight switch to parking lights so as not to drain the battery. Come back, and the locks are unlocked. This has happened twice. Play with key in, turn on, key off and out, and the locks locked and unlocked a couple times with me in the car as I sat there a bit waiting to see what would happen.
- Once, putting the cable back on, a small unit on the fender well on the passenger side under the hood kept clicking. I haven't looked up what that is yet. It's in about the middle, behind the air filter box.
- Occasionally, the door chime chimes with the door closed.
- Twice, while turning the key to start the car, something under the top left of the dash was buzzing weakly.
- Jimmying with the key in the ignition - in, out, left, right, doesn't seem to change the behavior.

In Alaska, I had a car that the headlights would go out when you were driving at about -40F. I thought it was a contact shrinking. The first time this happened, it was cold for here, say 10F, and this truck doesn't like the cold. Shop couldn't get it to do it there, even after sitting outside all night.

This time, there was heavy rain. A car guy in the office is speculating about a wet connection somewhere grounding or shorting.

I'm wondering a bit about the ignition switch or a bad or wet connection, but I'm not averse to replacing some other parts to see. The problem will be how infrequently it occurs. I'm not sure how I'll know when I've cured it.

Does this vehicle have an aftermarket alarm system? Even if you don't have a FOB or use it, it might have one, and that could be an issue. Just a thought, since having the door locks actuate themselves is highly unusual.

Also, just to clarify, if you turn the headlamp switch to "park" lamps, they headlights go off, but what happens if you turn them all the way off? Do they stay on?

Also, this headlight thing is intermittent right?

:ranger:

 

[Weetabix]

There's a sticker on the window that says "This vehicle protected by Toyota VIP vehicle intrusion protection," and there's a small plate on the parking brake cover with two lights and wires running from them. I've never seen them light up or noticed this thing do anything. Key is just a key, not a fob. Nothing about it in the Owner's Manual. I suppose I could try to chase that down and remove it.

Yes, the headlight problem is intermittent in the sense that it will do it for a couple of days, then stop for months, then do it for days again. For reference, it's stopped now. Maybe my buddy's wet connection theory... holds water.

If you turn the headlights to "park," the headlights go off. If you turn them either on or all the way off, they go on.

Looking at a manual with schematics, several of the body chassis components go into a body ECU (?). I don't have the manual in front of me right now, but I think that's what it said. Not sure if that's a wrong tree to bark up, though, because I didn't see, on a cursory examination, that the lights went there.

 

[IBallEngineer]

There's a sticker on the window that says "This vehicle protected by Toyota VIP vehicle intrusion protection," and there's a small plate on the parking brake cover with two lights and wires running from them. I've never seen them light up or noticed this thing do anything. Key is just a key, not a fob. Nothing about it in the Owner's Manual. I suppose I could try to chase that down and remove it.

Yes, the headlight problem is intermittent in the sense that it will do it for a couple of days, then stop for months, then do it for days again. For reference, it's stopped now. Maybe my buddy's wet connection theory... holds water.

If you turn the headlights to "park," the headlights go off. If you turn them either on or all the way off, they go on.

Looking at a manual with schematics, several of the body chassis components go into a body ECU (?). I don't have the manual in front of me right now, but I think that's what it said. Not sure if that's a wrong tree to bark up, though, because I didn't see, on a cursory examination, that the lights went there.

The door locks are in fact very connected to the Body ECU, but as you say, the headlights are another thing altogether. This is why I am stressing the AFTERMARKET alarm. Not any Toyota alarm. The aftermarket installers sometimes butcher things up, and of course the alarms have modules that can cause weird things too.

I've been busy and have to run now too, but I'm going to give you a series of checks to do WHEN you have the headlight failure, do you have a test light and multimeter?

Also, look under the dash on the driver's side for any NON factory wiring and/or connectors. Don't just rip things out, identify and eliminate as you can. I'll post later today!

op2:

 

[Weetabix]

Doing a little bit of searching on the forum, and I came across a link to this: alarm info

My car locks the doors when you turn the key and unlocks when you turn it off or remove the key (can't remember). That's a feature of this alarm.

I never had a fob. I may need to look further into the alarm system.

 

[warriorwagner]

I have an electrical issue also, sometimes when I turn off the lights, the interior lights start to blink between dim (like when the lights are on) and off (like when the lights are off). So the interior lights don't actually go off and on, but blink between bright and dim, like click.....click......click pretty fast.

Does anybody know what causes that?

Thanks,

 

[Weetabix]

Quick trip to the parking lot - I have a VIP ECU under the driver's seat.

The little unit under the hood that was clicking the one time I had the hood open and was searching around does not appear to be the same as the glass breakage sensor in the link above. It has two plugs coming out rather than one. But it's on a pretty heavy bracket to the fender well, so it could be some sort of shock sensor. The bracket looks way to sturdy for that little piece. But who knows.

I'm not good at tracing wires, but maybe I need to follow the wires from the ECU under the seat and see if they might be shorting somewhere along the way?