Help!!! - Latching Relay to "sink" a 12VDC <20mA load

I am a noob to Arduino, I know it can be made but just don't know how!!!

I need to build a single pulse latching relay using an Arduino Micro. The relay needs to sink a 12 V <20mA current to GND.

The actual app is controlling a set of LED Driving Lights in a motorcycle where a pulse switch sends a 12v pulse to toggle the on/off state, where on is OPEN and OFF means GND.

The lights have a built in controller that allows you to DIM the lights in a range from 100% to 4% and override the dimming function by sinking the load in one of the pins.

The idea is to set them in a low setting to use them as running lights and me able to override in case you need full power.

It is a very simple app but it is driving me nuts.

I'd appreciate your thoughts in terms of reliability, meaning whether the arduino is stable for this function or it my be affected by heat, vibration etc. and also how would you achieve this using the Arduino micro.

Thanks in advance

Mckanna

You identify how to latch the relay, but how do you plan to unlatch it? What relay? what does you code do now that is driving you nuts?

Paul