Humidity..

[Sorin]

Hello

I have a 1983 MB W126 300SD 421k km.
5 weeks ago i took the beast to the car wash, i wass the only guy in the car wash so the boys did a very good job, so it took around 20 minutes, it was very humid inside
I tryed to start the car no luck, got boosted car started fine, got home the car didn't start however if i boosted it was starting ( i drove it for one hour, shut down the car try to restarted no luck).
So i decide that it was my batery, changed for a new one, everything was fine.

yesterday it was snowing/raining and humid got to my friend house and the car wasn't starting, i boosted the car and she started, drove it for about 30 minute got home shut down the car, try to restart the car wouldn't start..

Where should i start looking ?
My alternator ? ( i do have the little batery light on my dash sometimes is on sometimes is off when i'm accelerating the light is off)

But if my alternator wasn't working my battery wouldn't last for 5 weeks of starting/driving...
My batery is new so i will take it out of the equation.


Any suggestion ideas are welcomed