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Hey to the Eric and the car guys. A friend of mine has a 2005 f-150 xlt 4X4 and when he has the air on the out side of the windshield is fogging up, and has to use the wipers to clear the window. He says that he brought to Ford and the guy said some kind (overflow) of tank is clooged. They have a drain hole that will let the fluid drip to the ground, and they took a small rod and shoved it up the hole. This worked for a few days but is back to fogging up. anybody have any ideas. Thanks
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What I think the Ford tech was talking about is the drain for the HVAC case. It’s not a reservoir or tank of any kind, it’s just a drain. Any humidity that goes through the evaporator while it’s working gets condensed into water. The HVAC case can also collect dust and dirt and, sometimes, small garbage items from owner negiligence can fall into the vents or defrost ducts. When the tech opened up the clog, he didn’t necessarily get all the dirt & debris that clogged the drain. The dirt probably settled back in and blocked off the drain all over again. If you can find the drain hole, you can make your own stab at the blockage and try to collect the water condensation while it drains out. This might give you an idea of what’s blocking the drain & might be able to determine if you need to pull the HVAC case and clean the case directly. What I can’t make sense of with this, is how it fogs the outside of the windshield. Usually, when you get a blockage in the case drain, you wind up with soggy carpet on the floor boards. Is his heat and AC always stuck on defrost by chance?
Thanks, I asked him about the defrost and he says the when foot or vents are selected there is a small amount of air coming through. Told him to try all selections and in all cases he does feel air coming out through the defrost. Any idesas?
I wouldn’t worry about a little bit of AC air creeping through the defrost. I was more worried about it being stuck full bore on defrost while running AC. Then I could see a problem with condensation on the outside of the window. Since I’m out of any good ideas, just follow through with finding and unclogging that case drain for now. If you can’t solve a problem yet, you can at least start eliminating variables.
As pointed out, I believe the tech was referring to the AC drain.
But a clogged AC drain would not cause the outside of the windshield to fog up. Honestly, that may be normal. If you live in a warm humid area this could be the reason. In the same way a water glass can gets condensation buildup on the outside of the glass because of the warm moist air contacting the cold glass, the same would be true for your windshield when the AC is on. In the end there may be nothing you can do about this. Perhaps rainx the windshield to prevent it building up. More info on solving HVAC problems here.
http://www.ericthecarguy.com/faq/solving-automotive-hvac-problems
Good luck and keep us posted.
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