Alternator not charging when driving in rain

[Gutter Man]

I have been experiencing this problem with the buzzer or beeping noise for some time now everytime it rains. Last year I took apart every possible connection under the coach, cleaned with electric contact cleaner, dielectric grease then after snapping back together sealing with liquid electrical tape or spray on duct tape. Oil sending unit included as well as all grounds on frame. It took me many hours to accomplish this task and am still having the alternator issues.
I did disconnect the beeper under the dash last year on the way to Bristol Tenn but didnt have any issues with the charging system at that time or any other that I noticed.
Now a few weeks ago I went to Tyler,Texas from Wisconsin for a week with a bunch of my buddies with no rain and no problems running the TV with the inverter as well as other things while driving. When my business partner left for the SuperBowl to go to Dallas (yes right back to where we were) he went right through the rain and then snow storm on the way. This is when the charging system failed to the point that the Abs light came on as well as the alternator light and eventually the engine shut down and the generator would not start.
After pressing the battery boost on the dash he was able to get to a truck stop but eventually that even stopped working. I think the Trombetta relay may have given up. Stuck in the snow in Missouri they took the battery lead off the chassis side of the trombetta relay and hooked it to the coach side thus connecting all batteries, started the Geny and away they went with no ill effects for the rest of the trip to Dallas. He had left it hooked up like that on the ride back but did not run the Geny and had no charging issues. Charging system worked fine riding home in dry weather.

Sorry for the long story but is there anything we can do to shield the alternator from getting wet while driving? I really see no way to shield it.

This is the first time either of us have been more or less stranded because of this issue but I would like to fix the problem if there is a fix.

Thanks

[Mike Canter]

Have you tried a new fan belt. A lot of times if the belt is too loose or glazed they slip when they get wet or damp? Is it on a serpentine belt or a separate V belt. If on a serpentine belt then is the tension good?

[Gutter Man]

I have thought of that myself. I know the tension is plenty tight. It is a serpentine belt and have also sprayed it with belt dressing.

[Midniteoyl]

Belt dressing sucks

Even if the belt is tight, it doesnt mean its not glazed and slipping.. belt dressing wont improve this for more than a few minutes. Yours is an '05 and if its the original belt, its about time to change it..

Your could also open up the alt and make sure the diodes are not 'sparking over' when the air is moist (like spark plug wires will do).

You do know that when it 'died' and then got jumpered to the coach batts, that they are what was running the engine, right? At least until the alt started charging again.

[Gutter Man]

Yes you are correct the coach batteries were then powering the engine. The Generator was then charging all 6 batteries when it was started also. It was better than sitting on the freeway in a freak snowstorm where they dont have any equipment to clear the roads. Sometimes you have to do whatever it takes to get to a safe or reasonable place to figure out your next move, if you know what I mean. I am going to look into the belt a little deeper and see if that is what the problem is.