condensation on inside windows
 

I have an 88 300e. Whenever it rains, I get heavy condensation on the side and rear windows . I do not use the recycle air button ever. The rear window can be cleared using the rear defogger button. The front side windows but not the rear side windows can be cleared using the heater.

When it is cold, I get frost on the inside windows. The rear window can be cleared using the rear defogger button. The front side windows can be cleared using the heater.

These fogging/frosting problems appear when I am driving and when the car sits unoccupied.

Any ideas where the moisture is coming from and/or how to get rid of this problem?

Thanks.

Make sure you have the a/c running at all times. The a/c system removes humidity from the air.

Thanks. I'll try the recirc. It'll be hard to run the AC this winter. I live in Northern Ontario and today it's -25C! Brrrr.

Could there be any other solutions in addition to what you've helped me out with?

I often get thick frost on the inside when I leave the car parked. In summer, the windows steam up while the car is parked. Other cars parked around me do not seem to have the same problem.

If you have the center button depressed, even with the knob to full heat, the a/c is always running, even though you are not aware of it.

MB designed it this way to remove humidity from the air.

By center button, do you mean the "auto" button for fan speed?

The A/C or the defrost must be ON in order for Recirc to remove moisture. If you recirculate the air without A/C or defrost on, it will increase moisture in the cabin.

But you're right -- your car should not do this. You have a water problem. And it doesn't take much moisture in the cabin of these cars to make them fog up. The reason is that they're built so well, they're practically air-tight. On my '92 201, the doors still shut hard unless I have a window cracked, or another door open. And if I turn the heater on Recirc without the A/C or defrost on, the windows will start to fog up in about 60 seconds. (Amazing for an 11 year old car with 144K miles)

I've never had a leak problem with my car, but a couple of the favorite causes for leaks in any car are:

1) Plugged drain hose/hole for the sun roof.

2) Plugged drain hose/hole for the A/C condenser.

If it were me, I'd check both of these.

Jeff Pierce

Yes, I mean the auto button.

My opinion is worth $.02 (and with an extra $0.99 you can buy a cup of coffee) about the water problem. I don't think you have a water problem.

Thanks Jeff.

Where are these drains located?

Thanks S.

SEARCH!!
 

Walpole,

You may have condensation inside the car. Check for dampness in, on, and under the floor mats and in the trunk.

Use the 'search' to find many posts about this topic and numerious solutions!

Environemental (water) leaks have many sources; seals, grommets, holes, etc.

thebern

I'm not sure where they are. Post the question, maybe someone else has an idea.

Jeff Pierce

There's one other possible source for extra water vapor in the cabin that I've had happen on a Saab. I noticed a similar situation, along with a slight coolant smell--turned out there was a small leak in the heater core! Once that was fixed the foggy windows and the odor both had vanished.

I believe Paul was referring to the "auto" button on the horizontal row of buttons, not the fan speed button (although this too should be on the "auto" setting). This is the center button. The one to its immediate right is the "economy" button which turns off the AC compressor.

Personally I'd bet you have a stuck air door which is keeping your car constantly in the recirculation mode. Do you hear anything when you do push the recirc. button? (That's the switch with the circle of arrows.) You should hear a vacuum sound and the sound of the door moving. If you don't, it would mean the door is stuck in the recirc. position.

Thanks everyone.

I do have water which accumulates in the footwells on the driver's and passenger's side. I've dried out the baffles and covered them in plastic under the floormats. But there is still a little water in each well. I guess I need to check the drains suggested. Are there any drains in the wells themselves?

I'm not sure how to put the defrost on and the recirc at the same time. When I use the major defrost button on the left hand side of the heater a/c controls, the recirc while not go on. When I use the button second to left, the recirc button can be used but I don't hear any door opening or vaccuum sound. The cabin does fog up quickly though.

I can't try the a/c recirc combination because the a/c gas needs to be recharged. It leaked out last winter. I'm getting this fixed in the spring.

Does anyone know where to get good 2nd hand motors/regulators for the rear windows? Is it worth using used parts for this?

Thanks

Keeping a window slightly open will also help with your problem.
In our clod climate, I have leaned not to let the ''recirculation'' system on for an extended period of time. On ''recirc'', the inside (damp) air is being constantly recirculated which only make the problem wost. I use it 10-15 minutes when it is very cold than switch it off. The cold outside air is much drier than the inside hot/damp air.
it is also a good idea to clear the heater air intake (below the windshild wiper) of any snow. As it melts, water and damp air are sucked into the system.
JackD