The 28" Multi-Function Rear Facing Chase LED Light Bars both have a Red Power and a Black Ground wire that should be connected directly to power for the brain of the light bar. The individual trigger wires need to be connected to switches or they need to be receiving power from whichever application they are wired in order to function according to the the specific trigger. Red and Black wires need to be receiving power regardless of whether the trigger wires are being powered in order for the light bar's functions to work. Connecting the trigger wires control each individual function of the bar. When the trigger wires receive power, they activate the specific action that is associated with the trigger wire color according to the instruction manual. Applying power straight to the trigger wire without the red and black wires connected to the power source will not work.
If a function of the light bar is not working correctly we suggest first double checking that the bar is receiving direct power via the RED and BLACK wires. Next we suggest checking if power is getting to the trigger wires using a multimeter to show if power is going to each trigger wire.
When initially installing the bar we suggest testing the functions before wiring the bar into the vehicle. This can be done by attaching the Red and Black wires to the battery to make sure the brain is powered. Then individually touching each trigger wire to power to activate its effect.