That's very kind of you @seanjordan20. I did end up ordering this (https://www.fcpeuro.com/products/bmw...ng-12527514236), but even if it is the correct connector, I'll still have to track down the correct terminals and plugs, which I don't know the specs for. So if you see it at your yard and can snip it, great -- happy compensate you whatever you think is reasonable for the part, your time, postage, etc. Thanks!

 

I'm sure you guys know better than I do, since this is the first repair I'm doing myself on this car –– but seems like the compressor motor must have burned up (that's why the connector melted) due to, as you say, constant power caused by bad relay (most likely), bad EHC, ride height sensor failure, clogged air dryer, or air leak.

I've struggled to diagnose though because it happened when my wife took took the car on a trip for a week. When she returned, the rear was on the deck. 40amp air suspension fuse was blown. Inspecting the compressor, I discovered the melted electrical socket housing.

I don't think it's a leaky air spring or left/right air supply lines. I guess maybe one side could sprung a big leak that caused the compressor to run continuously and fail, which then led to the other side losing air. The air spring and supply lines don't have any visible defects. Ride height sensors pass the eyeball check too. Pointless to check the busted compressor's dryer, because car needs new compressor anyway. EHC looks normal and I have never experienced the spare tire compartment flooding issue (not sure if is a potential problem for all E61s or if it was corrected at some point). So relay failure is the prime suspect.

I have replaced the compressor, double air valve (supply), relay, fuse, suction hose, filter, as well as the dust shield (https://www.turnermotorsport.com/p-1...uine-bmw-part/) (the foam was falling apart and since I live on a dirt road figured I should replace).

When I can supply power to the compressor (need connector!), I'll be able to find out if its something other than the relay...