Foggy Windows

Our 1997 Volvo 850 wagon’s air conditioning died over the summer and to fix it, our mechanic had to put in a new evaporator core. Now we have air conditioning, but the windows fog up all the time and in order to keep the windshield clear we need to run the air conditioner to take the moisture off the windshield. The mechanic checked the heater coil and it was dry and he cannot figure out what is wrong.

Some days it looks like we have been on lover’s lane for hours with all the fog inside the car and it is dangerous as we can not see clearly out the windows.

Any suggestions on what else to check? We look forward to your ideas.

This is a common problem. It is nearly always caused by the owner leaving the fresh air switch in the Recirc position. Then the mechanic overlooks this setting. Go out to your car now and verify the position of this switch; it should be set to Fresh Air. Let us know.

Doesn’t your car normally run the AC in the defrost setting anyway? I agree that having it set on recirculation will fog the windows.

Let’s hope it is because you have it on recirculate. It is possible that you have a small leak in the heater core. Check your coolant level amd make sure you are not loosing any.

Checked and the recirculation switch is not on. Also checked the coolant level and no problems there either. Still piuzzled and now that it is getting colder the fog is becoming icy. Let us know if you have other thoughts/ideas. Thanks

Go out to the car and cycle the fresh air switch while carefully listening for the door to open and close. It is possible that the mechanic broke/disconnected/jammed the fresh air door and it is stuck closed regardless of switch position.

I’m going to suggest that there is moisture getting in somewhere. If there is a leak, water will be absorbed by the padding under the carpet. Once it’s soaked in there it’s difficult to get out, but if there’s water there it would explain the fogging.