Defrost not working

77cruiser · 04-24-07, 08:13 PM

Whenever it rains my windshield and windows become a foggy mess. Anyone have this problem? Do i need to rebuild the heater or replace hoses?

Poser · 04-24-07, 08:15 PM

Are you sure that your blower motor is moving air?

Are you sure that the air it is moving is going through the heater core?

Are you sure that the defrost plate is flipped up, directing air towards the defroster ducts/tubes?

I learned long ago to have a towel in the truck, along with a scraper.

fjwagon · 04-24-07, 08:19 PM

Same here. I have a towel stowed away for this reason. I'm still debating if I should replace the fan assy. to one that performs better than the one that is currently on there.

Poser · 04-24-07, 08:25 PM

Blower motor options/upgrades from the F A Q <---- this is a link

GetsUThere · 04-24-07, 08:41 PM

Does the fan come on when you turn it on?
Does warm air come out of the heater when pull "warm pull" and have the heater set to HEAT?
Does any warm air blow out of the defroster vents when you set the heater to DEF?

If the airflow is weak out of the heater and defrost vents but the fan runs and the air is warm, it's most likely bad (or disintegrated) foam seals. There is weatherstripping foam around the blower, both sides of the duct, and flat pieces within the heater on the flaps. As that decays, air leaks everywhere and it doesn't go where it's supposed to. You can get a kit from aatas1x if you need to replace foam in the heater or blower.

If the air blows but isn't warm after the engine warms up, you have a problem getting coolant to the heater or there's a bunch of junk that fell onto the top of the heater core (or both). If warm air comes off the bottom of the heater but not the defrost vents, the plastic tubes that go up to the vents may be missing or have fallen off the round lower part of the vent. Your heater's flaps also might not be flipping right when you move the control.

If the fan doesn't come on and no air blows, you have a wiring problem or bad blower motor.

Spud · 04-25-07, 04:28 AM

Untill I looked really close at the lever...I thought the control read: Heat/Vent/OFF....Then a few days later I realized it said HEAT/VENT/DEF.

* Make sure you have it on DEF and not OFF. (just being a wise ass).

On another note, the rain-X for windshield works awesome...They also make a product for anti fog-up, (may be called Rain-X anti fog?). Maybe try that out untill you can get it fixed mechanically.

Good luck...

77cruiser · 04-25-07, 09:57 AM

Could have given more info, The blower works. When i pull the heat to high it blows hot air pretty strong but when i switch it to DEF(NOT OFF) it doesnt come out up top. On another note when i only pull it out half way there is not even a fraction of the heat coming out. sounds like there could be a clog of some sort.

fjwagon · 04-25-07, 08:52 PM

I beleive when you pull it out half way, the circuit is using a resistor to slow down the fan. Pulling it all the way will speed up the fan(bypass resistor-located on top of fan) and turn the fan located behind the seats or if it like mine in the middle of the seats, under the console. May want to check for an "open" on this resistor. I have fixed this resistor in the past cus I'm a cheap bastard using "wire wrap". It's best to replace it but if attempt to fix it be careful not to change the value of the resistor.

Quote:

Originally Posted by 77cruiser

Could have given more info, The blower works. When i pull the heat to high it blows hot air pretty strong but when i switch it to DEF(NOT OFF) it doesnt come out up top. On another note when i only pull it out half way there is not even a fraction of the heat coming out. sounds like there could be a clog of some sort.

CRWLNRX · 04-25-07, 10:39 PM

I had the same problem and found out that the hoses from the heater slipped off the hose mount under the dash which is under the defroster vents. Got new hoses mounted them (difficult to reach) and they work great.

wesintl · 04-25-07, 11:04 PM

the other thing is sometimes the lever gets slop in it and doesn't close the flapper all the way. Reach under the heater and push it up or at least confirm it's closing all the way.

VTFJ40 · 04-26-07, 06:18 AM

Quote:

Originally Posted by CRWLNRX

I had the same problem and found out that the hoses from the heater slipped off the hose mount under the dash which is under the defroster vents. Got new hoses mounted them (difficult to reach) and they work great.

x2.

The 3 I've owned all had this problem when acquired.

Trollhole · 04-26-07, 06:23 AM

x3.

igotta40 · 04-26-07, 12:13 PM

Also: Open the fresh air all the way.