1998 Lexus LS400 Alarm Going Off Randomly!

[Oldfatty]

Hello

The ear-splitting factory alarm on my 1998 LS400 has been going off inappropriately for a few months now.  This usually happen just as I lock it, but not exclusively, or when I switch the engine off.  It does not immobilise the vehicle (can be driven with the alarm still sounding) and can only be stopped by unplugging the Battery.  So far I have dialled down the proximity sensor underneath the centre armrest and changed the batteries in the fobs.

Since the alarm doesn't have any noticeable effect other than deafening me, my next move will probably be to find the siren and unplug it.  I don't think the vehicle Battery is the problem as it's relatively new and doesn't have any issues.

Any advice would be much appreciated.

Thanks

 

[jimmythehat]

hmmm. nightmare... alarms generally triggered by movement/ proximity sensors. also 12v circuit being recognised by alarm./ drop in 12v Battery supply. door contacts .bonnet catch making and breaking a 12v circuit. 

[Newbie1]

Guess you've checked that there is nothing metallic in the cente console like coins etc. That set mine off. 

I just lock the car with the key which does not set the alarm. It is unlikely people will break into the car and the immobiliser will stop them going for a joy ride.

 

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