Hi all,

Perhaps I just noticed this recently and it's been doing this all along, but today I noticed that when I unlock the car and get in the car, the defroster was still one. Then after I lock the car, I can hear it's still on.

Note: The AC and everything else inside the car is OFF - including the REST function. The exterior temp is about 55 deg F currently, so it's not very cold at all. My guess is it shuts off shortly, and then turns back on when I'm about to get in. Otherwise, the batter would likely be dead already.

Anyone have this experience and/or thoughts on this?

Thx, and Merry Christmas to my MBWORLD friends.
Patrick

bump - merry christmas everyone.

this am, the car almost wouldn't start.
clearly the problem is still there - has anyone experienced this?
thx.

Patrick

Sorry, never heard of such a thing.

I do know that when i open my door, I'll hear some electronics humming from inside my engine compartment. Even in the garage, I'll put something in the passenger's side and when the door is opened - I'll hear it and it will run for about 5 seconds.

Try that in your quiet garage.

i haven't heard of it either. is ur merc equipped with auto defroster or something ?

My car has many options, but nothing out the ordinary. Some have asked me if I left the "REST" function in the "on" position and it's not turning off. However, I've tried this with REST in both the On and OFF position, so I don't think that's it. The fan is on each am when I go out to the car(unless the battery dies), and it's been very difficult to start(or I need to use jumper cables). Either way, I have an appt w/ MB dealer next week when I'm back in SF...was just curious if anyone knew anything, and also wanting to share because I know the some of the R's can be a bit quircky(while others are perfect and no troubles). Our car has never stranded us, though I've been to the dealer probably 4-5x/yr the past 2 yrs for a variety of warranty items.
PL

It sounds like you may need a new blower motor. I recently had experienced the same type of behavior (fan constantly running without key in ignition) and that was the dealer fix. Mine was caused by water pooling in the cabin air intake due to a blocked drain. The water then overflows onto the blower motor below. Thankfully this was all covered under my extended warranty. Good luck!

aha - that's exactly it.
mine had water leak into cabin last week, and I emptied out the cabin air intake.
the drainage plug was small, and it was just "dirt" - not even leaves or anything...seems like poor design to me.
after i cleaned the air intake, there's no more leak...but that's when this blowing started, and the fan is right below the airbox...thx for input.
thx for sharing - hope this is helpful for everyone.
PL

I completely agree about the design flaw. Apparently there was a TSB about it at some point and the fix was to just remove the rubber grommet/drain plug. The condition of mine was exactly as you described - just dirt/gunk buildup, not a leaf or twig in sight.

MB dealer just fixed my blower motor as it was under warranty. However, check this out. MB will NOT warranty the blower motor IF IT WAS CAUSED BY LEAKAGE - even if it's caused by MB's own internal design flaw with the cabin air intake!!!

Therefore, caution all - check your cabin air intake ASAP and use a paper towel to clean the drain plug. Otherwise, you risk paying for a new blower motor - even if you have warranty.

PL

Good to know...

Can someone tell us where the cabin air intake is? This is good to check out!

Yes - where is it on my 08?

The air filter exterior box is under the hood, right in front of where the front passanger's positioning is. if you open the hood, it's covered and nudged up near the front windshield. just pop open the 2 clips, and remove the cover...then remove the plastic grill(easy). Once you remove the plastic grill, you can use your flash light to see, but the box is about 8-10 inches deep and has a small rubbery drain area. use something to clear it out (mine was filled w/ water to the rim, so I reached in and used my fingers and wiped away some fine dust/mud).

Keep in mind, this is different than the interior cabin charcoal filter, which I think is under the glove box. this is connected to the exterior air box - which is why when the drain plug is clogged, all the water automatically comes into the cabin. to me, it's a pretty obviously design flaw.

bottom line, this simple drain plug (that didn't drain) is common for MB techs in TSB, especially for damaging the blower motor.

PL

Update:
Just picked up the R and it's running great.
I looked at the specifics, and it looks like a "voltage regulator" was shorted, and thus the blower wouldn't shut off.
That would seem like an easy fix, normally, but guess what?
The voltage regular and blower motor is one unit - price to fix?
$600 if no warranty.
Geez...not only a poor design MB with the air box/drainage, etc...but now I find out you chose a vendor who put these puts together?
PL

Not covered under warranty if the drain is clogged? Well, that'S BS and a typical answer from a auto mfg.

I'm taking my wife's car in tomorrow. Looks like I need to check and clean the drain before I go in.

agree w/ you assessment...be sure to see my comments on your other post and do not mention "leak" or plugged drain, or your blower coverage may get denied(they blame user for not cleaning the plug).
also, have them TEST the battery...and try to prove damaged. mine worked for another month...then crapped out.
PL

Can someone post a do-it-yourself directions on how to get at this plug and remove it.

Take a look at this thread. It details how to swap out your cabin air filters from the engine side vs the glove box, saving a lot of time. You can see where I've added pictures on page three I think it is, showing the bottom of the intake. The rubber gizmo has a wide flange and can be pulled out out with your fingers.

http://www.benzworld.org/forums/w251...ir-filter.html

My SA left a voicemail saying they had looked at the car and the damaged blower/short/leak was caused by water intrusion. I cleaned out the air intake before I took it over, so I'm not sure how they determined it.

It's not going to be pretty if they say I have to pony up for the repair, as the drain plug is still there and the car was there recently, so they could have removed it per the TSB then.

What I can't figure out is how the water is able to jump up high side in back whan the front is much, much lower. How does ~2-3" of water jump ~10" in back?

Funny thing, my CLK63 Black Series just did the same thing today. I was driving along and the front defroster fan suddenly went full bore for about 10 seconds without me having turned it on. It would then do this every 20-30 seconds and stay on for 10 seconds, and shut off. So I started screwing with the HVAC settings. Then I turned it totally OFF and it still did it. Shutting the car down made no difference.

My SA's first guess was also to think it might be a faulty regulator. Car has been 100% dry since Sunday when I washed it, and it never sees rain, so I think this is just a failing part.

Will be interesting to see what they find...

Mine was clean as a whistle, but because there was rust on the blower motor spindle top, they said the damage was from a clogged drain and not covered. That and all the leaves they said they found. Only one problem with that. I clean it all out and wiped it down. Baker Mercedes Benz in Charleston SC is crooked as it gets.

I think their postion is if you have your service done there, it might get fixed under "goodwill" but if an indy or you service your car, then your SOL.

The good news is that if they won't cover it, you can pull the fan/regulator out in about 15 minutes. Then 5 minutes to clean the circuit board with contact cleaner. You'll see the corrosion in some of the electronics. Or install a new fan from a vendor like Partsgeek, etc. for $275.

I'll try to post pix tomorrow, as I'm on my phone.

yes, i had the same problem, but my won't turn off til the battery is DEAD

Don

My 15 minute fix cleaning the circuit board didn't take. It starrted running again and we had a dead battery one night. Got a new blower via the web for ~$265 and spent 15 minutes swapping it out. The stealership wanted $575 to replace it.

I noticed wen I replaced it, MB changed the design so that water would collect in a small tray and drip out a hole on to the carpet.