Electrical gremlin with door lock + horn

[Good Times]

Just experienced a weird gremlin on my 00 Land Cruiser.

Symptom:

1 > Unlock door (via key fob or key hole) will trigger the horn to sound (even before the door is open). (no aftermarket alarm or factory stuff as far as I know of)
2 > key fob only unlocks and will not lock any doors
3 > manual key via key hole (driver/passenger/rear hatch) will unlock but will not lock door

It just started to happening yesterday and is driving me nuts cuz every time I have to unlock the door the horn goes off as if it's an alarm. Disabling the horn only works by inputting the (master or slave) key into the ignition and turning it to the "on" position.

I've tried to reprogram the key fob but that hasn't cured this problem. I'm more concerned about the fact that symptom #1 makes me think something is wrong w/ the electrical because I don't understand why the horn would go off when you're unlocking the doors.

Thoughts on how to attack this gremlin?

[DHC6twinotter]

Maybe the wireless receiver for the remote? Toyodiy is showing there to be a door control receiver somewhere. I would assume this also controls the horn. That would probably be the first place I would look, although I'm not sure how to go about trouble shooting that.

89741 RECEIVER, DOOR CONTROL
89741-60060 (01/1998 - 06/1999)
89741-60061 (07/1999 - 07/2002)

I'm showing a security warning computer assembly under the dash. Not sure if you would have this, even though you don't have a security system.
89730-60010 (01/1998 - 08/2000)
89730-60011 (09/2000 - 07/2002)

Might be worth a check.

Sorry I'm not offering much help.

[Good Times]

I'm able to unlock the door using the key fob so I know it's not the receiver on either end. Thought about that.

Just weird that if the doors get unlocked either via key fob or key hole (manually via the door/tailgate) the horn sounds.

gonna try to reprogram the key again... maybe that'll fix it?

[4x4mike]

Different vehicle and different problem but if I lock my door using the key fob I need to unlock the door with the key fob or I'll get the horn. If I know I'm going to unlock the vehicle with just the key I need to lock it using the door switches.

I've got one of the factory alarm/protection systems and I read somewhere of a way to reset it. It was thought that the reset would solve my issue. Maybe it will do the same for you. What about pulling a fuse or negative battery cable over night in hopes of resetting it.

I assume the door switches lock and unlock as you desire? Maybe one of those is sticking and causing your issues.

[Good Times]

Didn't think to remove the fuse. Will try that today when I get a chance.

The weird thing is the power door switch works for both front seats (unlock / lock) so I know it's fine. None of the outside key hole (driver/passenger/hatch) will lock the doors but the unlock works fine.

The remote will unlock only. The stupid panic button works.

Go figure!

[Bob98SR5]

Didn't think to remove the fuse. Will try that today when I get a chance.

The weird thing is the power door switch works for both front seats (unlock / lock) so I know it's fine. None of the outside key hole (driver/passenger/hatch) will lock the doors but the unlock works fine.

The remote will unlock only. The stupid panic button works.

Go figure!

Lance,

I saw this: http://www.justanswer.com/toyota/6w1hy-toyota-landcruiser-2000-landcruiser-horn-started-blowing.html

something about water leakage and corroding fuses.

[Good Times]

hmmm maybe a long shot but I will need to hunt it down.

the part that throws me off is the fact that both driver and passenger power door locks work. so there's no electrical issue that I can think of since it's not triggering the horn because I'm unlocking / locking the doors via power door switch.

what makes it even more confusing is that none of the key hole (driver/passenger/hatch) will lock but will unlock.

so this makes me suspect maybe the ecu went bonkers or the previous owner had some aftermarket alarm (which doesn't look like it to me upon quick inspection of the underside of the driver dash + engine bay) and there's a short in the driver door panel door lock trigger??

What I learned was on the LC, to disable the factory anti-theft system you need to tap the passenger unlock line because that one will unlock all doors which disables the anti-theft system. if you tap from the driver side then it only unlocks the driver door which then the anti-theft system will think the car is being opened "illegally" which causes the horn to sound.

Really don't want to start taking stuff apart so I'll just deal with it for now. :/

[Seanz0rz]

Strange.

On a conceptual level, it sounds like the keyless entry is failing to tell the alarm to disengage. And, it sounds as if they vehicle thinks that you have a door ajar, since the keyhole will not let you lock the doors.

is that a correct description?

[Good Times]

Sean,

Yes you have a point on the door not wanting to lock because it thinks the door is ajar. That's a good way to phrase it and this applies to both the remote and keyhole attempt to lock.

As for the keyless entry system failing to tell the anti-theft to disengage I'm kinda stumped cuz I've been driving with one set of keys w/ a dead remote battery and it worked fine. Go figure.

My gut says bad ecu but we'll see. Gonna slowly figure this one out. Not driving it every day so it'll just probably sit in the garage until I have some time to figure out why it's driving me nuts!

[Seanz0rz]

For me, I can lock the doors if they are open, but when I close it (at least the front), it pops the lock up. I have to hold the handle up to lock it that way. like an old car.

Is it possible the computer thinks one of the doors is open? Doesn't really make sense to me since when you do disarm it, the alarm immediately goes off.

I too think it is an ecu. problem is, it could also be a bad wire somewhere. I'd try to find someone with a similar 100 to swap ecu and see if the problem follows the ecu or is left to your vehicle. I will also try to dig up some info on those systems.

[Seanz0rz]

I sent you an email, Lance. It gives the locations of all the relevant ecus. If you need other diagrams, let me know and I will do my best to get it to you.

[Good Times]

Did a few more tests. All of the doors sensors are working since I see the door light go off once the door(s) are closed. Checked all 5 doors and all is good so I'm starting to narrow down to the ecu area. Gonna take apart the dash after the holidays since I really don't want to be playing garage mechanic when everyone is home for the holidays.

[YotaFun]

Sorry to be chiming in late on this, but have you checked to see if the hood switch is good?
I believe your model should have one, and if that goes bad sometimes could cause similar issues to what you are having.
Just something else to look at before replacing the ECU

[Good Times]

Did some more digging finally and I couldn't find a hood switch Avy. Looked for any electrical contact/wire everywhere but nothing.

Btw I did end up replacing the body/junction ecu but that didn't fix it so I'm still back at square one. Gonna try to tinker with it some more next weekend when i have some time.

The part that throws me off is that if I manually unlock the driver's door via the key fob the factory alarm goes off so something must be happening here that I can't explain. weird

[Seanz0rz]

Hood switch is built into the latch.

you can remove the latch assembly, disconnect the harness and check between the two terminals. When it is locked, there should be no continuity, when unlocked it should have continuity.

Also, try just unplugging and jumping it on the wire side. This should tell the ecu that the hood is closed.

[Good Times]

ok I'll have to check that out but my understanding was it was just a cable latch but I'll double check later today.

[Seanz0rz]

The latch isn't electronic in that it is still cable operated like every other vehicle. It just has a switch inside that says if it is closed or not, like the rear hatch latch on my 3rd gen.

[Kryptoroxx]

I had this same problem only I didn't have the keyless entry yet. Your problem is a faulty integration relay. I know I have a 4runner and you have a land cruiser but it is exactly the same problem. This is what it looks like for a land cruiser I think.

http://www.lcool.org/technical/90_series/PowerWindows/window.html



stamped and snail mailed

[BattleWagonActual]

I had a similar problem for about five minutes after installing a donor RS3000, in my 4runner. It's a bit of a long shot and I know you said you reprogrammed the fob, but have you tried wiping the system of all remotes and then reprogramming the fob?


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[Good Times]

I hope it's not the integration relay!!! Getting to that and removing it is a PITA!

Just got back home yesterday so I didn't get a chance to work on the LC but will be farting with it sometime during the week to see if I can figure out the bug.

I did wipe all of the keys and reprogrammed all 5 keys I have so I ruled that out right away.

grrr

[BattleWagonActual]

5 keys? I thought they could only learn 4.


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[YotaFun]

5 keys? I thought they could only learn 4.

Depends on the model, some are 4 only, some are 5 only, some are 4 regular keys and one valet key.

[BattleWagonActual]

Depends on the model, some are 4 only, some are 5 only, some are 4 regular keys and one valet key.

Oh gotcha. I'm the only one in my family whose Yota had keyless/alarm so forgive me if I'm not the most knowledgable. I just know the problems I went through with mine since I had to pull it from a 96 auto and install in a 97 5spd(the wiring harness is only 90% the same as I found out.) My dad had a 70 fj40 (obviously no keyless) and brother had a 90 4runner w/o as well.


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[YotaFun]

Oh gotcha. I'm the only one in my family whose Yota had keyless/alarm so forgive me if I'm not the most knowledgable. I just know the problems I went through with mine since I had to pull it from a 96 auto and install in a 97 5spd(the wiring harness is only 90% the same as I found out.) My dad had a 70 fj40 (obviously no keyless) and brother had a 90 4runner w/o as well.

Its all good, I aim to educate what I learned from my time as a tech at Toyota now if I could only remember more important things in life as how to do taxes and such -_-

Then from keyless entry and immobilizer keys you move to smart keys, then stuff really gets fun -_-

[Kryptoroxx]

Its all good, I aim to educate what I learned from my time as a tech at Toyota now if I could only remember more important things in life as how to do taxes and such -_-

Then from keyless entry and immobilizer keys you move to smart keys, then stuff really gets fun -_-

Fun....hmmm if by fun you mean mind numbingly expensive lol. We have had a scion for 2 years and the cheapest we can find an extra blank for is 150....dealer said 300

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[Good Times]

I should have been more specific. I have 3 remotes and 2 valet keys. But regardless I think my ecu accepts up to 5 or I think it does cuz I'm able to drive with any of the 5 keys. :)

Avy, I haven't looked for that hood switch but that's next on my list when I have some free time this weekend. So far I couldn't find anything in the service manual that says there's a switch at the latch on the hood and/or the latch below the steering panel. I'll figure this damn bug eventually.

thx for all of the suggestions! keep it coming!

[Kryptoroxx]

I hope you get your problem fixed. It was annoying when I had mine and I really wanted it fixed.

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[Good Times]

finally found a hood courtesy switch integrated into the latch mechanism. was doing the ol touch blindly with your fingers to trace a line and I think that's what might be the culprit.

gonna take the latch apart this weekend and clean up the contacts to see if it just got gummed up with crap. hopefully cleaning it up will resolve my problem!

just hoping it's not something else...

[Seanz0rz]

Glad to hear you found the switch in the latch. I've had pretty good luck with my fsm source, always nice to get a confirmation it's correct.

[Good Times]

Finally found the time to work on the darn issue over the weekend. Took apart the hood latch assembly in the engine bay and determined that it was a bad sensor. I just shorted the circuit so it shows "closed" all the time. The horn does not sound so I think things are looking good.

Just need to reprogram the keys remotes to make sure its able to lock cuz at the moment it still doesn't lock the doors. Just glad the damn horn doesn't go off every time I open the door!

thanks for all the help! will update again after I reprogram the fobs for the all clear. :)

[Kryptoroxx]

Hey that sounds great!