1999 ZX2 horn gone wild...

My girlfriend has a 1999 ZX2 with manual locks, which I would assume means it does not have the theft deterrent system/alarm. She got the car 4 months ago, and the theft light randomly turned on today for the first time. There is no wireless remote (since it has manual locks)...so the fact that the theft system (which shouldn't even exist on this car) randomly engaged itself is crazy. To top it off, now the horn/alarm is randomly going off. It sounds just like my '01 ZX2, which DOES have the theft deterrent system/alarm w/remote. Any ideas?!!! Or at the very least, is there a way to disable to theft system and keep the functioning of the horn? Thanks!

Hi, I'm not familiar with the ZX2 but this might still be relevant. I drive a diesel Escort Estate (station wagon, I think you call it over there - I'm in the UK). Mine is a '95 and it also has manual locks with no wireless remote, and it has the basic factory-fitted Ford alarm system. My alarm is triggered solely by the door switches, including the tailgate but I'm not sure about the hood. The primary function of those switches is to switch on the courtesy lamp when any of the doors are opened, but when the vehicle is parked and the alarm is set, those same switches are used by the alarm system as sensors, and if a door is opened then the alarm will sound. I'd start by checking if those switches all operate the courtesy lamp correctly and reliably - if they're intermittent when operating the courtesy lamp then they might also intermittently trigger the alarm system. I'm not sure if you mean the alarm is randomly going off when the vehicle is parked, or whilst you're actually driving it, but either way I would investigate the door switches - they're fitted into the door pillars and the door presses against them when it closes.

My alarm is set just by the action of locking either the driver's door or the passenger door with the key. The key operates the mechanical lock of course, but it also closes a microswitch located behind the door panel, and that's how the alarm system is activated.

I don't know how to disable the system, because I've never been troubled by false alarms so I've never had reason to find out. You should be able to park the vehicle without activating the alarm by using the self-locking feature on the doors. My driver's side door doesn't have the self-locking feature (to minimise the chances of a driver inadvertently locking themselves out) but it should be possible by doing it this way:

1. Leave the vehicle and close the driver's door, but don't lock it with the key - but DO make sure you have the key safely in your pocket first!
2. Now go around to the passenger door and reach across inside and press the lever to lock the driver's door.
3. Now depress the lever on the passenger door and then swing it closed.

Both doors will now be locked but without having used the key - therefore the alarm will not be set and you won't be troubled by false alarms. That should buy you some time while you find out how to disable the alarm system or until you fix the fault.

I can't guarantee that that will work on your vehicle but I suspect that it will. And don't lock yourself out with the key still inside! Anybody else have any knowledge on this?

Thank you for the information. I will check the door switches, but I don't think that's the cause...mainly because this car's theft deterrent system isn't even supposed to be enabled since it doesn't have power locks and the remote. It has never armed itself in the previous months of ownership, and we always lock the doors. With that being said, one of the door switches is broken...so maybe it's shorting out the system and making it do weird things. It's definitely worth checking. Thanks again for taking the time to help. Any other ideas are much appreciated!