50 amp power cord

This morning I was unable to remove the 50 amp power plug from the coach.  I killed the power and removed the 4 screws holding the cover plate.  The large male plug behind the cover plate had a melted spot about 2 inches in diameter and about 3/4 inch deep.  The male and female plugs were welded together.  After a lot of cutting and prying I was finally able to separate the plugs, both of which have to be replaced.  I was able to save the painted cover plate. The built in Progressive industries system never showed a error.  About a week ago I thought I smelled burning plastic, but couldn't find a source.  Upon disassembly I noticed all of the contact screws on the male connector were loose .  I suspect these loose contact screws caused the problem.  Just a heads up for other owners. 

Interesting.  Thanks for the heads up.

That's actually quite disturbing. I'm glad you found it before it caught fire.

Last summer, maybe in August, when my AC was running the most, I had noticed my 30Amp plug was slightly warm at both ends.  The cord contacts on the male end and the contacts in the PC's power wall socket were somewhat corroded.... But not loose like yours.   I shut off the breakers inside and used some 200 grit sand paper very lightly to shine them up and then applied a very thin coat of silicone lube to prevent any further oxygen exposure and corrosion.  Since that I've never found it warm. I fear the contacts inside the cord's socket end are corroded too, but I couldn't figure out how to get it open to verify.  Checking this is now an action on my annual maintenance list. I'll add to check that the parts are tight as well.

I know that corrosion is a better resistor than conductor. In your case the lose contacts were the resistor. Happy you discovered it when you did. Thanks for the alert.
Larry