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I have a 1998 one owner es300.(my Grandmother was the first owner) It's never been in an accident and only has 9100 miles on it. For the past 10 years, the car alarm goes off on its own. Nothing bumps the car or shakes it to make it go off. Sometimes it's in the middle of the day and worse at night. It was quite annoying to wake up to the alarm going off in the basement garage. no intruders or anything falling on it. Just completely random. To my knowledge there is no way to arm or disarm the alarm on the car. Even if I left the doors unlocked while running into a store or parked in my yard, sometimes just by opening the door, it would set off the alarm. I've changed out fuses and car batteries but it never fixed the issue. Sometimes months would go by without the hiccup but then there it was again reminding me something was up. So I every time I parked the car, I would lift the hood and remove the fuse for the horn, so when it would go off at least it wasn't disturbing the peace, but then it would drain my battery. So, a year ago I installed a battery disconnect switch. Now every time I park the car, I lift the hood, unlatch the battery disconnect switch and close the hood. No more battery drain and no more alarm going off, and no way for someone to steal the car or forget that I took out the horn fuse. It's inconvenient, but it works. I just have to use the key to manually unlock the doors and pop the hood to connect the battery in order to start the car. That's the only remedy I was able to find, due to Lexus being stumped over the issue. Super lame that this happens. I am curious to know if any of you have the same issue and what you have done to truly fix this issue?
There is no hood switch from the factory you must have an aftermarket system installed like remote start. On car alarms what good are they? Can blare for hours no one does anything except gets annoyed and wishes it would stop.
Do your headlights flash as well when the alarm goes off?
Originally Posted by LeX2K
There is no hood switch from the factory you must have an aftermarket system installed like remote start.
I may have missed something, I don't see any reference to the hood switch.. With that, interestingly enough, those actually do have a courtesy switch on the hood way back from 1993 model year, here is a picture of the lock that shows electrical connector.
But on the subject of aftermarket systems, do you have any extra fobs, strange buttons in the interior, or any other extraneous stuff in the car? Anything that can give away an aftermarket system basically..
Check the operation of each door switch, I once had an issue where one of the door switches got loose, so the alarm would go off at random, since the car would see that the door got opened while still being locked. Check that they are tightened securely, since the switch is grounded through the chassis, then check that all 4 work as intended, with no loose fit or lost contacts. You can also disconnect them all for the night to see if that will help, just make sure to plug them back in before using the car, since a complete lack of those can cause its own troubles.
I may have missed something, I don't see any reference to the hood switch.. With that, interestingly enough, those actually do have a courtesy switch on the hood way back from 1993 model year, here is a picture of the lock that shows electrical connector.
Interesting gonna look at my car later to see if it has that. Also will test if the alarm goes off with the hood up.
I stand corrected there is a hood latch detect switch, couldn't see the wire/connector but can feel it. Locked the doors (window open) waited 2 minutes popped the hood alarm went off.
There is no hood switch from the factory you must have an aftermarket system installed like remote start. On car alarms what good are they? Can blare for hours no one does anything except gets annoyed and wishes it would stop.
there are no aftermarket parts or alarm installed. Everything on the car is stock from the dealer. The alarm sounds randomly. Without opening the doors or hood latch. I hate car alarms as well. Completely worthless. But I need a fix other than a battery disconnect
Do your headlights flash as well when the alarm goes off?
I may have missed something, I don't see any reference to the hood switch.. With that, interestingly enough, those actually do have a courtesy switch on the hood way back from 1993 model year, here is a picture of the lock that shows electrical connector.
But on the subject of aftermarket systems, do you have any extra fobs, strange buttons in the interior, or any other extraneous stuff in the car? Anything that can give away an aftermarket system basically..
Check the operation of each door switch, I once had an issue where one of the door switches got loose, so the alarm would go off at random, since the car would see that the door got opened while still being locked. Check that they are tightened securely, since the switch is grounded through the chassis, then check that all 4 work as intended, with no loose fit or lost contacts. You can also disconnect them all for the night to see if that will help, just make sure to plug them back in before using the car, since a complete lack of those can cause its own troubles.
Hope this helps and best of luck!
Yes. No aftermarket parts or hood switch was mentioned in my original post. But you mentioned the door switch. Sometimes the doors unlock and lock or lock over and over on their own while parked. Could this be linked to the alarm going off on it’s own?
When you mention the “door switch”, what part are you speaking of exactly?
The wire loom going into the door could have damaged wires that randomly short out and cause your issue. I just got done repairing a harness for a car with this problem.
Yes. No aftermarket parts or hood switch was mentioned in my original post. But you mentioned the door switch. Sometimes the doors unlock and lock or lock over and over on their own while parked. Could this be linked to the alarm going off on it’s own?
When you mention the “door switch”, what part are you speaking of exactly?
It's the little buttons on the B-Pillar that let the car know when the door is opened or closed, below is the picture.
It sounds somewhat similar to the issue I had a while back, where a switch on the Key Tumbler fell off the door lock while stuck in the "closed" position, causing the car to think that there was a key turned to lock the doors at all times, here is the link with more information.
It's the little buttons on the B-Pillar that let the car know when the door is opened or closed, below is the picture.
It sounds somewhat similar to the issue I had a while back, where a switch on the Key Tumbler fell off the door lock while stuck in the "closed" position, causing the car to think that there was a key turned to lock the doors at all times, here is the link with more information.
Hope this helps and best of luck!
ok. I’ll check these out to see if they are sticky. Thank you so much for the picture and the link to the other post. The video in that post looks very helpful. I will give an update in the next few days.
08-06-22, 05:22 PM
1998 ES300 Alarm goes off randomly
