I’ve got a Toyota Sienna XLE, with well over 100,000 miles on it, and an expired warranty. Recently the anti-theft feature started to malfunction, going off at the worst times, especially 3am, outside the house.
There’s no extra alarm system, so it’s a factory problem, or a wear-and-tear problem. It happens at home, and when I’m out and about, usually within about 4 hours after the car has been driven. There’s nothing interfering with the keys, because I keep the van key on a separate fob.
My short term remedy was to pull the red #10 fuse in the box under the hood, out of slot nine, the slot which deals specifically with the horn and anti-theft feature. So now the alarm is dead, but so is the horn.
Is there any way to keep the horn, but ditch the alarm?