I found a weakness with the Garmin AMPS mount.

Recently my AMPS mount stopped supplying power to my Garmin Montana.  This was a bummer.   

Upon closer inspection, it appeared that the mount's center pin (the one that supplies power) was missing.

Even CLOSER inspection revealed that it wasn't really missing, it was just stuck and hadn't "popped out" the way it's supposed to.  A little WD40 and the pin popped right back out.

Now the AMPS mount is working normally again.  So as a preventive measure, you may wanna squirt some WD on those pins every few months.

I wonder if a dab of dielectric grease would be a better option?

I thought of that, but I'd rather not have it attract dust and dirt.