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2014 Mazda5 Sport: Tom's Hardware's Project Car Update

Installing Our Blind Spot Monitoring System

Installing the Premium Blind Spot Detection System isn’t for the faint of heart. It’s an involved process that requires fishing wires through the firewall and drilling holes in your bumper. As such, I enlisted the help of my father, a former Mazda-certified Master Technician. Installing accessories was part of his day job when he worked at a dealership more than a decade ago.

Before we began drilling into the car, Goshers’ instructions suggested testing the blind spot monitor on a test bench, which we did by hooking everything up to a portable 12V battery jumper pack. The package worked beautifully, so we started working on the front-mounted sensors. Proper installation is important; the sensors need to installed at a minimum height of 1.6 feet, but no higher than 2.3. Yes, that meant drilling holes in a vehicle less than three months old at the time. Nevertheless, the front sensors popped in with reasonable symmetry on both sides.

Next, we had to fish sensor wires through the firewall. This was particularly obnoxious since we chose to utilize the same grommet as the hood release. Accessing the firewall required that we pull the battery, its box, the air box and the intake piping. The sensors individually connect to a harness with a three-pin connector similar to those old CD-ROM audio cables. It's fairly wide and doesn't fit through tight holes particularly well. So, we had to remove the connector and feed the cable through using thin wire.

With the removed components back in place, we picked up our tools and headed to the back of the car for a little rear sensor action. The process was the same: measure, re-measure, use a punch to mark the spot, measure again, and drill a hole. Routing wire in the trunk area was naturally a lot easier.

Once the sensors were in place, we had to pick a spot for the control module. Goshers suggests installing it in the trunk, so we followed the company's advice. From there, running wire up to the front was easy since Mazda's lower trim panels pop off readily. The front harness contains the control module's 12V power wire, the sensor connection, and an interface for the indicator LEDs. We tapped a power wire from the vehicle harness that's only live when the ignition is in the On position.