Defroster not working

katmat

New member
I've got a 05 3500.
The heater control is not working. is there a cable behind the control knob/ If so how easy os it to get to. I get heat out of the center vents but not the floor or defroster, no matter how I
turn the controller.
Thanks,
Matt Murphy
 

cahaak

New member
There are cables that connect at the back of the ATC (which is the entire controller - all three knobs together). Check on the forum here for instruction on how to remove it. Just require removing a few Torx screws and some center dash pieces, fairly easy. The cable may have come off. You will just tip that control out, you can't pull it out the whole way because of the cables attached at the back. See what the status is, If one is broken, then you have a lot more work. In any case, make sure you lube them with some decent lubricant like 3 in 1 oil or such. Mine were quite stiff initially, I had checked them because my AC was not working and lubed them then. They work very smoothly now.

Chris
 

jmoller99

Own a DAD ODB2 Unit.
You might also check your cabin filter to see if its clogged up. When I bought my Sprinter I had similar problems. Changing the cabin filter allowed enough airflow to allow air to flow on the windshield and be directed to the floor.

I also ended up lubing the pull cables on the center vent control (you can get to them if the radio is out, otherwise, there is a lot to take apart on the console to get to them). However, I had one of the pull cables flexing under compression - I added a small spring to help pull it back (the console has to come apart to add it).

My fix is in the later entries here: https://sprinter-source.com/forums/showthread.php?t=2058
 
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hkpierce

'02 140 Hi BlueBlk Pass
I find the defroster is very inefficient. Before tearing anything apart, check by turning up the fan speed to 4 and closing all 6 vents - including the center 2. If that doesn't do it, then no choice.
 

jmoller99

Own a DAD ODB2 Unit.
I agree that the defroster mode is not very aggressive. When its real cold and snowy out, I find I go thru a lot of windshield washer fluid to keep the windshield clear. Ice on the windshield is also solved in that way.

When I could only get warm air thru the dash vents, it was solved by spraying graphite lub on and in the pull cables behind the air/heat/vent control unit (the one with the knob you are trying to turn to get the air directed to the floor and/or windshield). This is a common issue.

You might consider replacing the light bulbs in that control unit if you have it apart to lubricate.
 

cahaak

New member
Concur, the defrost of the windshield is not very effective. In the manual, they state you need to run the fan on 4 to get it to work. It does not seem to deliver that much air volume to the windshield, but on 4 with the temp on complete hot, it does do the job. But, you wait a long time if you don't manually scrape the outside in the morning!

Chris
 

thinice

2005 tall 140WB 160K
Had a similar problem on my neglected 2005. The cable was kinked and needed lube. Not to difficult (I did it, and I am not a mechanic) to pull the unit far enough out to straighten or reattach, then lube.
 

outbound

06/2500/140
i'm also having this problem (on an 06(dodge)2500)
no air comes out of the windshield/defroster vents, no matter what settings, no matter how fast the fan.

is there a precise setting of the knobs that does the trick, or does the control system (cables, vents, flaps) have a problem?

reason i ask about this, is the manual is somewhat less than clear (to me) about how to set the knobs to get airflow onto the windshield

the guy at the local dealer said something to the effect that: 'oh yeah, have seen that before, had to take the entire dash/console apart to fix it, cost appx 2000bux'

HUH?!! (getting the idea these things are like a B.O.A.T. = 'Bring Over Another Thousand' ;)

any insights on this one very much appreciated (esp since we got the white stuff up high this morning and time grows short to work outdoors)
 
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jmoller99

Own a DAD ODB2 Unit.
If you have a clogged cabin filter you won't have much of any defroster air flow. When did you change it last?

I change mine every 2 years. It's in the engine compartment, above the engine.
 
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outbound

06/2500/140
hey jmoller, thanks for the comeback!

'cabin filter' ?
didnt know there was one - or guess maybe that have noted something about it somewhere - but my other guess would be that it likely wasnt ever changed.

will look into that, soon as i get finished changing the glowplugs (which will happen soon as i figger out how to get the elec conns unplugged ;)

but a question, if you/anybody could maybe show me a photo of how the knobs need to be set to have airflow out of the defrost vents?
the manual is somewhat less than helpful (and theres like waaaay more settings than on any other vehicle i've ever...)
 

cahaak

New member
The knob needs to face straight up for air direction. That is the only way to get decent air flow for the defroster.

Chris
 

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