Every time my air compressor would shut off I got a loud annoying pop through the radio. Even if the radio was off I would still get the pop.
I knew it couldn’t be good for all the electronics in the truck so I tried a mod I got from a golf cart forum.

Diodes across the relay signal terminals need to be installed in performance carts to protect the electronics.
I put one of these diodes on my truck this week. 100% of the pop is gone.

I used this one
ACC-KIT-CSD-1

 

Some pics of what I am talking about.
1st is the backside of the marine rated, continuous duty heavy duty solenoid.

The discs are rare earth magnets sold as wire tie supports. The solenoid just sticks to the inside of the fender.

Next is the actual solenoid with the diode across the two terminals (polarity critical)

This is mounted under the truck, so to keep is from getting soaked I keep this heavy plastic bag over the solenoid.

Last pic shows the solenoid stuffed as high as I could get it. The clear hose with red stripe is the fresh air intake for the Zenith compressor.

Stays nice and dry.

 

Thanks for posting about this. I have had that on different vehicles in the past and that looks to be a simple solution. I've had to ground RCA outputs on head units, shield and ground chases for speaker wire and all kinds of different fixes to get rid of interference, pops and static over the years.