How Do I…Wire a GPS Tracker or Dash Cam in a Fleet Vehicle?

From the API Signal install team.

Every GPS tracker, dash camera, ELD, and asset tracker we install lives or dies on the wiring behind it. A clean install lasts the life of the vehicle. A sloppy one comes back as a callback, a dead unit, or worse, a blown fuse on a truck that's supposed to be working. This chapter covers the basics we hold every installer to.

What three wires does a GPS tracker need?

Most fleet devices need three connections. Find them, test them, and confirm them with a digital multimeter before you connect anything.

Constant 12 volt (battery). Has power at all times, key on or off. Keeps the device's memory and clock alive and lets trackers report while the vehicle is parked.

Ignition (switched 12 volt). Has power when the key is in RUN and stays on during CRANK. Drops to zero in OFF and ACCESSORY. This is the wire that tells the device the vehicle is on. A wire that drops out during crank is not a true ignition wire, and the device will log false starts and stops.

Chassis ground. Bare metal on the body or frame, not a painted bracket and not a plastic-mounted stud.

Test all three with a meter. Do not trust a wire because the color matches a chart. Wire colors change mid-year, by trim level, and by plant.

What gauge wire should I use for a tracker or camera install?

Use multi-strand copper wire with good insulation. Solid-core wire cracks under vibration. The size depends on the current draw and the length of the run.

For runs longer than 10 feet, go up one size. When in doubt, go bigger. Bigger wire never hurts. Smaller wire gets hot.

How do I fuse a power wire in a vehicle?

Every power wire that connects to the battery or a constant 12 volt source gets a fuse, and the fuse goes within a few inches of the source. The fuse protects the wire, not the device. If the wire shorts to ground somewhere behind the dash, the fuse is what keeps it from becoming a fire.

Size the fuse to the wire, not to the device. A 16 AWG wire gets a fuse no larger than 10 amps, even if the device only draws 1 amp.

Fuse taps (add-a-circuit) are acceptable at the fuse panel when used correctly. The tap goes on the load side, the tap's own fuse matches the wire you're adding, and the original circuit keeps its original fuse.

Where do I ground a GPS tracker?

A bad ground causes more strange problems than any other single mistake. Devices reboot, cameras drop video, trackers report low voltage that isn't real.

• Ground to bare, clean metal on the chassis or body. Scrape away paint, primer, and grime.
• Use a ring terminal and a star washer. The star washer bites into the metal and holds the connection through vibration.
• Do not share a ground with the radio, the amplifier, or anything else noisy.
• Do not ground to a seat bolt, a door hinge, or a bracket bolted to plastic.
• Keep the ground wire short. A long ground wire is a resistor.

What is the right way to splice wires in a vehicle?

Every connection is soldered or crimped, then covered with heat shrink tubing. No exceptions.

Butt connectors. Fine for joining two wires of the same gauge when crimped with a proper ratcheting crimper. Use the heat shrink type when available.

Ring terminals. For grounds and battery connections. Match the ring size to the stud.

Quick disconnects. Useful where a module might need to be swapped later. Cover them so they can't short.

Solder and heat shrink. The strongest splice when done right. Tin both wires, join them, heat until the solder flows, then heat shrink over it.

What we don't use. Scotch-lock style tap connectors and electrical tape alone. Taps cut strands and loosen over time. Tape unwraps in heat. Both come back as callbacks.

How do I route wires through a vehicle?

• Run wires along factory harnesses where possible and secure them with nylon ties every 8 to 12 inches.
• Encase exposed runs in split loom. It protects against chafing and makes the work look factory.
• Use a grommet in any hole you drill. Bare metal edges cut insulation.
• Go through the firewall using a factory grommet or a factory-cut hole whenever one exists. Drilling the firewall is the last option, not the first.
• Keep wires away from heat sources: exhaust, manifold, heater core lines.
• Keep wires away from moving parts: pedals, steering column, seat tracks, window regulators.
• Never route through or bundle with the yellow airbag harness.
• Leave a drip loop where a wire enters from outside so water runs off instead of following the wire in.

How do I test an install before closing the dash?

1. Re-check every connection with the meter.
2. Confirm the device powers up, reports, and shows the correct ignition state with the key off, in accessory, in run, and during crank.
3. Tug-test every splice and every tie.
4. Make sure nothing rattles, nothing hangs, and nothing can be seen or kicked by the driver.

A driver should never know we were in the vehicle, except that the equipment works.

This information is provided as a guide. Verify every circuit with a digital multimeter before connecting to it. Proper installation is the responsibility of the installer.