A brief guide to installing a car alarm



We spoke with Phil Jones, Crutchfield Product Support Manager, about installing an alarm.

Protecting your vehicle, and everything in it, from theft is certainly a concern for most people, and an alarm makes a great preventative measure. But how much security do you really need? And what should you expect if you try to install it yourself?

We spoke with Phil Jones, Crutchfield's Product Support Manager, about the ins and outs of car security. He gave us some useful general tips concerning choosing and installing an alarm.

How much security do I need? Is there such a thing as too much?
With all the alarm choices out there, each with its own set of features, it's easy to get overwhelmed when trying to decide which alarm to buy and install. Basic packages generally consist of a control module (also referred to as the alarm brain) and a few sensors that trip when the doors are opened. Upgrades in higher-end alarm packages tend to include features like hood and trunk protection; starter interrupt circuits; glass-break, impact, or motion sensors; remote start modules; and inputs for remote functions, such as trunk releases and window roll-up modules.

We asked Phil if, sometimes, there's such a thing as too much security.

"There's such a thing as spending an awful lot of money and an awful lot of time on a system that can still be defeated," he said. "You can make it more difficult, but you cannot eliminate a professional [thief]. You can discourage."

Alarms are still pretty useful, right?

"I think they're better than not having an alarm," he laughed.

So, from a security standpoint, what's the basic difference between lower-end and higher-end alarms?

"Security-wise, the lower-end alarm is going to offer you everything the higher-end alarm [will]...typically the upgrades are features."

In the end, if installed correctly, a basic alarm package is effective as a theft deterrent. If you'd like more features, such as auxiliary channels for remote applications, higher-end alarms are perfect. But if it's simple security you need, you can certainly take your budget into consideration and still feel reasonably confident.


Some alarm packages, like the Crime Guard 745i3, include a wide variety of security and convenience features.


How difficult will it be to install my alarm? What should I expect?
Not surprisingly, installing a car security system is inherently more complicated than installing, say, an in-dash receiver. Phil emphasized that time and patience are your two best allies when attempting to put an alarm in your car.

"For a basic alarm installation, a weekend should be available," he said.

The most common calls the Tech Department fields concerning alarms have to do with finding, testing, and connecting all the wiring. Phil said that "most service books that have electrical schematics will have what you need" in terms of wiring diagrams. However, the installation process still involves "a lot of panel removal to get to everything you need to tap into," as well as accessibility problems. Space is often tight, and it might be difficult to test and tap the appropriate wires. Again, patience and time are absolutely necessary.

For testing the wiring to which you're connecting, a multimeter (a tool that detects and measures the electrical current that passes through a vehicle's wires) is essential. Make sure, however, that you're completely familiar with how to use it before you begin.

Phil emphasizes, "...if you're going to install an alarm yourself, you should already own a multimeter. If you buy one [specifically] to install the alarm, you're probably not where you need to be."

Confidence in your ability to understand and work with the electrical system in your car is also a must. Phil says that you should "understand the systems of the car you're going to mess with, and make sure you feel good about messing with them."

"The systems you're tying into [when installing an alarm] are different from a stereo: you can make a lot of mistakes with a stereo and you'll only affect a limited part of your car. But with an alarm, the ignition harness is kind of an important thing [laughs]. Power door locks are not critical [to the functioning of the vehicle], but [damaging them] can be a costly mistake. You can live without them, but nobody wants to, and it's expensive to fix...[and they're] really close to the body control module [a vital vehicle system], so that's bad. So I would say that that really increases the importance of knowing what you're reading, and the quality and integrity of the connections."

"When you evaluate your ability to successfully install a device, equate that to the reliability of your vehicle after you're done. If you're pretty good, then your vehicle will be pretty reliable. If you're kind of good, your vehicle will be kind of reliable."

So you can install your alarm. You just have to make sure that you're patient, comfortable working with complicated electrical systems, confident in your ability to read wiring schematics and make strong connections that won't come loose over time, and that you've given yourself plenty of time to get it installed correctly.

Do you have any good installation tips for me?
Phil noted that the most important aspects of making any alarm work as effectively as possible are wiring integrity, alarm module placement, and LED positioning.

Strong wiring connections, not surprisingly, help ensure that your alarm will work exactly as it's supposed to, for a long time. However, the routing of the wires also plays a vital role.

"After the alarm's installed and everything's tied in, tape the alarm wires to the factory loom [the plastic shielding that conceals factory wiring], and tape the harness going to the control module."

Concealing the wiring adds to the alarm's effectiveness — if a thief can see the alarm wires easily, he can cut through them quickly and render the alarm useless.

The same goes for the module, or alarm brain. To maximize effectiveness, "it's all about control module placement, stealth...put the control module upside down, or somewhere high, so that you can't just look at it and...[makes a cutting noise]."

Like the wiring, obvious and exposed module placement makes life much easier for a car thief.

Finally, installing the LED is incredibly important, especially as a theft deterrent.

"LED placement needs to be very visible, because that's really the only deterrent you've got. Essentially, any exposed part of the alarm to a potential thief should look factory. Weird LED placements give away a home-install job, as do wires hanging under the dash. It's encouraging [to a thief]. It's like a challenge instead of a deterrent."

As with the wiring and the module, placing the LED in a highly visible, logical position can make all the difference between a break-in and discouraging a would-be thief.

Hopefully, these tips will give you some idea of what to expect when installing a car alarm. Thanks, Phil, for taking the time to speak with us!
Gift Card The Great Gear Giveaway

Sign up for our email newsletter and then enter to win a $500 Rewards Card.