Defrost problems 1992 300D
 

The defrost mode is pretty much un-useable its so hot...in the rain I cant defrost my car.

It fogs up so fast that I literally have to pull over.
Just the other day I was running from a Tornado in North Texas
and I had to stop to clear my windows.
I noticed that the air coming out of the vents regardless of position was luke warm and humid.

Any suggestions



Wayne:(

Wayne,

It sounds like your air conditioning is not turning on when it is supposed to, as the defrost mode is supposed to turn the heat on full and the A/C on full, and direct the hot, dry air to the windshield. When it is working this is very effective at drying off the windows.

On my 350SD if the car got really wet in a rain storm the A/C would sometimes shut off. I had to pull over and shut the car off, then restart and the system would work ok. I never figured out if that was normal or not, and it did not happen all the time, only when it really caused some anxiety. In a heavy downpour the last thing you want is to have to pull over, shut off the engine and restart the car so you can see the road.

I think your car may have the same issue, and it may come from the liquid level in the A/C air cooler box from condensation rising too fast, possibly due to a sluggish drain. I don't have the car anymore and have not experienced the problem in the manually controlled system on my 190E, and have yet to experience those conditions on my 1988 300E or my 1998 E300D TurboDiesel.

I hope this helps you. Jim