Clicking noise when the truck is in park and idling

[KMyrick]

My 2015, 3500 has a clicking noise that comes from under the right side of the cab. I hear it when the truck has been running and is idling. Any ideas? Maybe the exhaust system?

 

[EHoxie]

It is the DEF injector. Each click is a pulse of DEF being sprayed into the exhaust system

 

[KMyrick]

Thank you for that piece of info EHoxie. Glad I can explain it someone if they ask me.

 

[Dieselnerd]

If you have your inside temperature set to auto or A/C, it can also be the A/C compressor cycling when it's warm outside. I'm in the SW part of the country right now with 85+ degree temps. If I open my hood with the engine idling I can look down at the A/C and see it cycle on and off and clicking.