Help Diagnosing New Electrical Gremlin

Electrical click sound from trailer wiring harness behind driver's side kick panel

Hi Scotty/all who help out here on the site,

I recently had an electrical issue pop up that I wanted some help with. I have a 2010 Nissan Frontier and it is equipped with a trailer tow package from the factory. I replaced the blower motor not too long ago, and few days after, I noticed that there was a noticeable single click sound that started every time I would turn the driving lights on or shift into reverse to engage the back up lights (Has 6spd manual transmission). When it was really cold, I discovered that there was also a quick little flicker of the lights occasionally while toggling back and forth from driving lights to headlights. I was able to trace the clicking sound to the trailer wiring harness...see picture above. There is a blue relay in the harness where the clicking sound is coming from. I tried swapping out the relay with another, but it does not get rid of the noise I described. I tried checking all the fuses associated with the trailer lights, but all were fine. I have been cleaning all associated connectors with CRC electrical cleaning spray in case there was some gunk that got in there, but nothing has gotten rid of this noise. Any advice you can give me in terms of things to check or try would be greatly appreciated!

Relays are supposed to click it’s normal for them to click

Thank you for your reply Branden. I know that relays click, but I was never able to hear a loud clicking sound like this in the cabin of the truck before now. Even if the clicking noise was "normal" that still doesn't explain the intermittent flickering of the headlights when the sound occurs.

have the alternator and battery load tested first, places like auto zone do that free

Scotty, the battery is brand new back in October of 2017. It starts up fast and smooth. Interstate Mega Tron Plus. So that shouldn't be an issue. Can I test an alternator with my multimeter and not have to remove it from the truck?

Just tested both the battery and alternator with multimeter. They both are in great working order and I am getting solid voltage readings.