Car Alarm Experts?

[FresnoRob]

I recently bought a 2002 Ford F-150. It doesn't have a space in my garage so I have to park outside. It may have had a factory alarm once but no longer does. So I bought a Viper alarm from and had it installed by Best Buy. The thing goes off by itself. Tried turning the shock sensor all the way but it still happens.
I found via a Google search that Fords may or do send a signal to the door locks periodically to verify the doors are locked. Anyone had experience with this or the fix? It's not a high $$ alarm all I really wanted was remote door unlock and something to go off if the door got opened.

[Kyle1886]

We had the same problem with my wife's '06 Ford that the dealer installed upon purchase. After about 6 months I disconnected it.

(That's when we found out the dealer had disconnected the factory installed alarm so the could sell the $$$ add on. The factory alarm DOES NOT trigger for no reason).

Don't know the brand of the add-on, but don't think it was a Viper.

Good luck, that get annoying in a hurry.

Kyle

[Mitch]

I bought a 98 Suburban last year that had all kinds of lame aftermarket electronics in it including a car alarm. The alarm would go off whenever it wanted, occasionally when I got into the car to take it to work at 6:00 in the morning. There was no reliable way to make it stop. My neighbors must have loved that.

The solution was to remove the damned alarm.

[sealocan]

Properly installed and adjusted alarm should not be going off,

it's a shame nobody has those.


I also think the old factory alarms might be more stable than some of the more recent ones that have sensors to monitor voltage (trying to notice someone opening the door / using the ignition) but the problem with that is some modern vehicle"s electronics periodically do things the trip that type of sensors.

I do believe a good alarm installation place should be able to eliminate /shunt/bypass the type of voltage monitoring (it might just a switch on better alarms.)


But my guess is they are going to try and sell you an upgrade first.

[FresnoRob]

I'm game if I need to spend a bit more for a better one but not lots more. The truck isn't worth that much. Thanks guys.

[Carcassonne]

My GMC came with a factory alarm, but it could be turned off when you used the key instead of the FOB to unlock the door. The bad thing is that someone can jam a screwdriver into the door and also turn it off. I found that out the hard way. I then purchased a GM factory add-on alarm made by DEI (Clifford, Viper, etc) which could not be turned off by using a key or screwdriver. I was also able to add other sensors to the DEI alarm.

I had several false alarms with the DEI alarm before I figured out what was wrong. My truck has a battery saving feature. If a dome light or other battery draining device is left on, the truck's computer (BCM) shuts it off after a while. The alarm brain for some reason sees this as a door trigger and sets off the alarm.

Check to make sure you don't have a dome light on or have something else attached to the vehicles wiring that will drain the battery. A USB phone charger or blue tooth device may drain the battery. Something attached to your cigarette lighter socket may also cause a drain. If you have to attach something that drains the battery connect it directly to the battery terminals so it bypasses the vehicles BCM (Body Control Module).

This website may help. Do a search to see if other people have had the same problems. http://www.the12volt.com/


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[vg247]

I'd take it back to Best Buy and have their installers trouble shoot it. In addition to what's been said already, sometimes the Vipers can have defective sensors which still sets the alarm off despite being turned way down.

You shouldn't have to do the leg work, these installations and alarms typically come with a pretty good lifetime warrantyf I'm correct.

[Kyle1886]

I scrounged around and found the alarm that was removed from my wife's car. It's a Karr 4040a.

If someone wants a lightly used alarm that is guaranteed to annoy your neighbors and drive you batty, I''ll part with it for FREE
(FTF Vista).

Respectfully
Kyle

[Mitch]

Alarms seem unnecessarily complicated.

I have an old El Camino with the battery installed under the bed (there's a compartment under the front of the bed in most El Caminos). The cable between the battery and the ignition runs through a switch hidden in the passenger cab. If I want to, I can turn off the switch before I leave the car, and it will not start.

Simple.

A bit more complicated, but even more effective was a set-up I had on an old Malibu convertible: the steering wheel could be removed and replaced with a cover that locked on with a key. No one was driving that car anywhere without a steering wheel.

[Carcassonne]

Alarms seem unnecessarily complicated.

I have an old El Camino with the battery installed under the bed (there's a compartment under the front of the bed in most El Caminos). The cable between the battery and the ignition runs through a switch hidden in the passenger cab. If I want to, I can turn off the switch before I leave the car, and it will not start.

Simple.

A bit more complicated, but even more effective was a set-up I had on an old Malibu convertible: the steering wheel could be removed and replaced with a cover that locked on with a key. No one was driving that car anywhere without a steering wheel.

Nowadays they just tow it away siren blaring and everything. Most people think it is just a repo job. You would be surprised at how fast a tow truck can snatch a car.


.

[Mitch]

Nowadays they just tow it away siren blaring and everything. Most people think it is just a repo job. You would be surprised at how fast a tow truck can snatch a car.

I've always thought that would be the easiest way to snatch a car these days, though I've never seen it done. Alarm won't help you there either.

[Big Lan]

Fords of that era have a BCM (they have a fancier acronym for it that I can't remember) that falls asleep after a certain period of inactivity (I seem to recall it being roughly 90 minutes, but it's been the better part of a decade since I've dealt with one).

Basically, the wires that go to the individual door pins drop signal voltage, and the aftermarket alarm, if installed incorrectly, senses the change in voltage and interprets it as a door being opened, which sets off the alarm. What needs to happen is the door pin (might be a reed switch; again it's been awhile...) needs to be diode isolated from the BCM, and the door trigger wire for the alarm needs to be tapped in downstream of the diode. Here's a crude text diagram:

BCM-->diode-->insert door trigger here-->door pin

They'll probably have to do each door individually, and in that instance they'll have to diode isolate each door trigger from the others as well. It sounds more complicated than it actually is. They should have access to DEI's Directechs software (DEI is Viper's parent company), and the procedure should certainly be laid out in there somewhere (at least it used to be - like I said, it's been a while...).

[Whiterabbit]

If all you want is an entry alarm, why don't you just unplug the shock sensor and re-test?

[FresnoRob]

I'd take it back to Best Buy and have their installers trouble shoot it. In addition to what's been said already, sometimes the Vipers can have defective sensors which still sets the alarm off despite being turned way down.

You shouldn't have to do the leg work, these installations and alarms typically come with a pretty good lifetime warrantyf I'm correct.

Thanks,
It's going back Wednesday, I was just trying to get some idea if someone here knew so I can be ready for them if they didn't know how to fix it.

Fords of that era have a BCM (they have a fancier acronym for it that I can't remember) that falls asleep after a certain period of inactivity (I seem to recall it being roughly 90 minutes, but it's been the better part of a decade since I've dealt with one).

Basically, the wires that go to the individual door pins drop signal voltage, and the aftermarket alarm, if installed incorrectly, senses the change in voltage and interprets it as a door being opened, which sets off the alarm. What needs to happen is the door pin (might be a reed switch; again it's been awhile...) needs to be diode isolated from the BCM, and the door trigger wire for the alarm needs to be tapped in downstream of the diode. Here's a crude text diagram:

BCM-->diode-->insert door trigger here-->door pin

They'll probably have to do each door individually, and in that instance they'll have to diode isolate each door trigger from the others as well. It sounds more complicated than it actually is. They should have access to DEI's Directechs software (DEI is Viper's parent company), and the procedure should certainly be laid out in there somewhere (at least it used to be - like I said, it's been a while...).

Thank you in my search I saw one or two posts about needing a diode, but none explained it as well as you did. It's a Super Crew Cab so 4 doors.

If all you want is an entry alarm, why don't you just unplug the shock sensor and re-test?

This model has the shock sensor built in. I have adjusted it all the way down and it still happens. So it's defective or it's not the problem. But if I end up replacing the alarm I'm leaning toward buying one that is seperate so I can leave it out.

Thanks again everyone.

Rob

[Iknownot]

The public has been trained to ignore alarms after years of false ones. No one pays attention in the slightest.

If you are doing your own install, wouldn't it be better for you to wire up your own kill switch instead? I think you'd have a much better chance of some one giving up after spending too much time trying to get your car started vs getting scared off by an alarm. I don't think any security system does anything to keep people from messing with your car.

A hidden kill switch could do a lot to slow someone down.

I used to know a radio installer that used to do kill switches using factor wiring so that you couldn't tell by looking at the harness and car wiring which one kept the car from starting.