I bought my 95 SC300 not too long ago & upon purchasing the old owner told me that the alarm has issues. Every time I try to unlock it from the drivers side the alarm goes off, so i usually open it from the passenger. Just recently I went to unlock it from the passenger side as always & the alarm went off. I tried the reset with the key but it didn't work. I was able to get inside but the only way the alarm will cut off is if i put the key in the ignition. The car won't crank now. I went to disconnect the battery & as soon as I reconnect it the alarm trips again. I've tried the key reset as I reconnect the battery but still no luck. If anyone has any suggestions it is much appreciated. Thanks

 

Sounds like you've got the same problem I was so rudely greeted by the first time I unlocked the car after purchasing it. The little plastic sensor on the back of the lock cylinder gets detached or just goes bad, so it doesn't send the signal to the alarm that the door has been unlocked properly with the key.

https://www.clublexus.com/forums/lex...de-doesnt.html

Post #13 details the fix. I added info in post #16 for how to go about getting at it. It's easily the most difficult thing I've attempted to do on this car, from the standpoint of nearly-impossible access, so be prepared for a challenge!

It sounds like you may need to source spare connectors for both doors if the pass. door is doing it now, too...

BTW, putting the key in the ignition silences the alarm but activates the kill switch. I'm stumped by Lexus' reasoning on that. I'm unsure why your alarm comes back on when you reconnect the battery, though. That leaves me somewhat less than 100% confident your problem is the same as mine was.

 

I managed to reset the car after a while but regardless my alarm is still giving me issues. I'll look into the details you gave me for the fix. I'm just going to hold back from locking my car (which I hate the idea of) until I can get this figured out. I really appreciate the response!! Thank you!

 

Check out eBay item #281356411293. That's what you'll most likely need. Pretty good price (shipping is a bit high, but most sellers will make it more reasonable if you combine a few things), and you get a spare door handle to boot.

Mine was only the driver's side, so I just got in the habit of unlocking from the passenger side and taking the long walk of shame back around.