Databus Modules

As far as installing a security or remote-start system on your truck goes, depending on what make and model you drive, you might have an install that is fundamentally seamless and effortless-or it could be a bear and a hard slog for your installer. Whether or not your installer can integrate with databus makes the difference.

In issue No. 3, we discussed how factory databus relates to your stock head unit. The average car or truck has 70 different computers onboard, linked by databus, running an astounding 35 million lines of software code. Automakers use multiplex wiring (sending multiple digital signals over the same wires) to save weight and cost and to facilitate the computer control of functions like engine management and transmission control.

These in-vehicle networks are complex, and glitches occasionally pop up. According to the Los Angeles Times, automakers spend as much as $3 billion a year fixing software issues to make their databus systems more reliable, because approximately one-third of all vehicle warranty claims are related to electronics or software.

But the automakers are not the only ones riding the 'bus. Vehicle security and remote-start installers have an ardent interest in databus, because having a module from companies like Directed and Trilogix that both reads and writes to the databus can mean the difference between an easy one-hour install and a painful three-hour install-and one or three hours of labor costs passed on to you.

"Any time we can avoid removing door panels to integrate with the power locks, that's a benefit," said Kevin Willard, mobile electronics instructor at The Snake Pit installation training school in California. "It definitely benefits consumers to avoid unnecessary disassembly of the vehicle.

We recently spent several hours at The Snake Pit with Willard, a 21-year veteran of the industry, as he demonstrated our options-with and without databus-on an '03 Chevy Silverado. "When I started in this business, it wasn't nearly so painful to install alarms as it is today," he said. "The difference is data." In order for the alarm to also provide power door lock/remote keyless entry functions, it needs to integrate with the door computers, and there are two ways to do that: an easy way and a hard way.