Air conditioner vibration issue SOLVED

[GlennFC]

I have a Dometic Brisk 13,500 BTU air conditioner but my problem could happen to anyone with a roof top A/C. One of my A/C units was very noisy and caused a vibration through the whole coach. I could see the squirrel cage fan from inside and it appeared to be OK. Motor end play was minimal.
I removed the roof top cover and checked the bladed fan that is on the opposite end of the same twin shaft motor.
It had a large mud hornet nest that caused the fan to be badly out of balance.
Mud removed, fan blades cleaned, and now my AC is quiet and the vibration is gone!
If you experience this issue, try checking both fans before taking your RV in for an expensive service call.

[Gregg.H]

This post contained some very useful information! My AC exhibited a severe, shake-the-RV level vibration when I turned it on after it was stored for a couple months. Searching this forum for "air conditioner vibration" brought me to this information and sure enough! The exact same problem with mud wasps building a nest on the back (the side you can't see until you take the whole thing apart) of the condenser side fan of AC.

Gregg