Copyright Goodheart-Willcox Co., Inc. 512 Section 5 Electrical and Electronic Systems Technology Some vehicles have a remote parking system that parks the car without the driver being inside the vehicle. The system automatically controls the acceleration, steering, shifting, and braking. Trailer Assist A trailer assist system helps the driver during backup maneuvers when a trailer is attached. The driver can view the rear of the truck and trailer in the dash dis- play showing the rear of the vehicle. One system has the driver turn a small knob on the dash to activate the system, which then steers the truck while backing up its trailer. The system uses the video image as a guide. Servicing Security, Navigation, and Driver Assistance Systems Servicing vehicle security and navigation systems usually involves part replacement. However, the prob- lem may sometimes be a bad antenna or power feed problem to the unit. Normally, if a unit is getting power and is grounded but fails to work properly, the unit must be removed for replacement or repair. See Figure 38‑15. Service Procedure To find the source of the problem in an advanced system: 1. Try operating the failed system to verify the customer complaint. 2. Try to pinpoint any external problem that could keep the unit from operating. This includes a bad antenna, dead ECM, no display, or damaged, dirty, or misaligned cameras, radar, or sensors. 3. Check for blown fuses and for power going to the unit if the unit does not turn on. 4. If the power supply circuit has a relay in it, make sure the relay is working. Plug-in relay testers are available. 5. Make sure the unit has a good ground wire attached properly. 6. Review stored trouble codes, which may indicate the source of the problem. Remove bezel Pull off display bezel Remove side cover Remove lower cover Unscrew and remove navigation unit Disconnect wiring harness and antenna Side Cover Detail Remove side cover Goodheart-Willcox Publisher Figure 38-15. Note how front bezels come out of this vehicle dash. You must remove a few screws and then pull lightly on the part to free it from rubber mounted clips and dash.