1989, 245
153,000


My drivers side windshield (inside) fogs up when the defroster is set to the warm position. The passenger side does not fog up but remains clear. I noticed a hissing sound about once a minute that seems located under the dash. Also every fall I notice that leaves work there way into the grill air vents in front of the windshield. I also noticed a smell of burnt leaves, accompanied by a quick short burst of smoke.

I read some archives but did not find a problem like this. I have the interior panels removed and the sound of vacuum at idle seems to be working for the three main control buttons. I did not see any leaks. I removed the drain hose on top of the tranny well and it looked dry. Pushing in the re-circulation button causes a rectangular door flap to open (in the dash at the bottom, close to the inside firewall, and pushing it back out closes the door). On # 1 blower position the air flow is not to forceful. Each number up does increase the amount of flow to the windshield. Also, closing the upper dash vents from air flow, greatly increases the amount of air to the windshield.

Last night, I tried to blow out and vac out leaves/debris from hood grill and inner rocker panel area ducting (assuming they are connected?), but I did not see any leaves or debris come out. Where did those leaves go? Could they be blocking up the system and causing moisture? After the clean out attempt, the problem still came back but then later it seemed to work ok. So, I will monitor it some more to be sure.

I must admit that whole area is so crowded with wiring, vents, relays, connectors, and it is so crammed in there, that it is hard to understand just how the entire system is supposed to function. For one thing, I do not understand how air and water can enter the outside grill but how does the water get separated? ... where does it go? ...what is the route of the air v. the water, starting at the outside grill vents?

thank you,
diyer