The Lightguard transmitter unit is self-powered and has a 7 pin socket and plug and is plugged in between the towbar and trailer. The small (90 x 65 x 25mm) battery powered (PP3) receiver/display unit has a visual representation of your trailer lights with LED’s to indicate the status of the trailer lights.   Normal mode Once the transmitter is plugged in, switch the receiver unit on. As each trailer lamp is illuminated the appropriate light will be displayed on your Lightguard receiver. If a fault is detected the receiver will flash the appropriate light together with the fault light and sound a warning alarm. This mode should be used to check your lights when hitching up. Stealth mode After a period of 30 seconds has elapsed the unit changes into ‘stealth’ mode to prevent distracting display of lights, particularly at night. In this mode no lights are displayed unless a fault is detected. If a fault is detected, the unit returns to normal mode and flashes both the relevant light and the fault light as well as sounding the warning alarm. Teach mode Your Lightguard unit will come with a ‘default’ setup. However, if your trailer has an unusual lighting configuration or does not have a rear guard (fog) lamp you can use the ‘teach’ mode to let Lightguard ‘learn’ you trailers lights configuration.