2005 Climate Control Issue, (air only comes out of defroster and top vents)


New member
I have a 2005 2500 with just over 100k on it. I bought it from a really shady dealer in upstate NY (learn from my mistakes!) who has since gone out of business...

Before I purchased the van I noticed that the temperature control knob seemed to have no resistance whatsoever, and could actually spin 360 degrees... And the vent selector knob had too much resistance.

Somehow, I convinced the dealer to replace the climate controls for me. He bought a new unit form a nearby MB dealer, and had his "best and brightest" install it.

Everything seemed to be working fine, but now that it's winter here in upstate NY, I have noticed that no matter where I put the vent selector knob, the air is only coming out of the defroster vents, and the vents that are on the dash, facing the seats.

On really cold days, my feet go numb, and I have ended up purchasing those disposable toe warmers for the longer drives.

So my question is... Is it possible that the "mechanic" at the dealership incorrectly installed the control unit? Would I (or a MB/Dodge/Freightliner mechanic) be able to take it out and fix the issue, which I assume is a cable not being pulled, or will I have to buy another $300 part for my van?

Thanks for your help!!


Active member
The temp control knob should definitely not turn 360. It should rotate clockwise from 12:00 (hot) to 6:00 (cold) and stop at both ends.

The dash vents on the horizontal surface of the dashboard can only be turned off physically at the vents themselves. They always emit unmodified outside air.

Foot heat for my T1N is pathetic. I always have cold feet, even though the cabin is warm. I get some heat down there, but not much. Might be pilot error, though. The dash controls are cryptic.

There's a users manual posted here somewhere.


Own a DAD ODB2 Unit.
There are discussions about how to fix your problem on the site (with pictures - https://sprinter-source.com/forums/showthread.php?t=2058 - its long, but you will find lots of info there), In general, the issue is binding in the cables that are operated by the air-redirection knob, If you pull the radio out, you can get the area you need to lubricate (if you have the stock Sprinter radio, you will need to know the radio codes to re-enable it afterwards). If you don't want to pull the radio, you will have a great deal more to take apart (might as well change the 2 lights in that console while you have it all apart).

I bought spray cans (with thin plastic pipes that you could plug in) of lubricant (not WD40) and fed the lube on the plastic parts that are rotated by the knob, and also forced spray lube into the cables that are operated when you rotate the knob,

This is a common problem.

NOTE: Getting the radio out needs special tools (If you have some thin/strong steel, you can make your own - I ground off the sharp part of the blades of 2 cheap steak knives so they fit in the 2 slots under the radio - you'll find these much stronger than the tools from Crutchfields). If you have the original stock radio, this is a good opportunity to replace it with a much better radio. Use the search in the blue bar for lots of info on that topic.
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