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Discussion Starter #1 (Edited)
1998 ML320 Only hot air from vents no cool outside air

1998 ML320
With A/C off or on I am getting hot air out of the vents and even when I trying to vent in outside air w/ AC off nothing but hot air from vents. Any DIY ideas I can try to fix this problem? Thnx.
 

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Discussion Starter #2 (Edited)
Did a search and found this post/reply

Go into archives, many people have same problem, very common, DETANE did a video of how to replace it by removing glove box, you have access to replace from there about a 2 hour job, dealer will tell you that you need to remove dash, bullshit for more money, dealer can do it in probably 30 min or less. If you dont know how to go to archives, go to search this forum on top, type in air blend actuator, go to posts, Good luck

My question is my '98 has the turn controls/cable, no motor. Could this be the issue?

Added Information:
1. Compressor and clutch are turning and not cycling on/off
2. When I turn the temp dial to red the vents will blow hot air, but back to blue not cold air.
3. #44 Fuse is good.
 

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BMW 2007 X3 3.0si, 1999 ML 320 -Sold-
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Did a search and found this post/reply

Go into archives, many people have same problem, very common, DETANE did a video of how to replace it by removing glove box, you have access to replace from there about a 2 hour job, dealer will tell you that you need to remove dash, bullshit for more money, dealer can do it in probably 30 min or less. If you dont know how to go to archives, go to search this forum on top, type in air blend actuator, go to posts, Good luck

My question is my '98 has the turn controls/cable, no motor. Could this be the issue?

Added Information:
1. Compressor and clutch are turning and not cycling on/off
2. When I turn the temp dial to red the vents will blow hot air, but back to blue not cold air.
3. #44 Fuse is good.
Im confused, are both the compressor and clutch working? Are you saying that even though its <40F outside (im guessing) you're still getting hot air coming through the vents if its on the blue?

When I had my ML and lived in Syracuse, I'd have to drive sometimes with it right in the middle temp dial because it would heat up so much that full blast was unbearable.
 

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Discussion Starter #4
Im confused, are both the compressor and clutch working? Are you saying that even though its <40F outside (im guessing) you're still getting hot air coming through the vents if its on the blue?

When I had my ML and lived in Syracuse, I'd have to drive sometimes with it right in the middle temp dial because it would heat up so much that full blast was unbearable.
Yes both the clutch and compressor are turning. Temp here in FL is mid 60's. I also checked the low pressure side tubes and one is warm and the other is cold.
Could it be the blend doors? On blue with AC on or off getting warm to hot air. If I turn the AC off and turn the dial to lowest setting on blue still get warm air.
 

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Tell us the circumstances of how you started to get heat. Living in Fla. you must have had the controls on A/C for most of the year. Did you touch the control to receive heat and that's when your problem started?
 

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1999 ML320 Elegance, BMW R1150RT, SAAB 9-3
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i'm not a fan of the '60s (the decade that is :p ) but i would say that if it is mid 60s (f) you should get mid 60s f air blowing from your vent when the temp control knob is at cold and the ac is off.

does sound like your blend door may be the issue. did you check to see if the air gets warmer as the vehicle warms up? that would be a strong indication.
assuming you cleaned out your pollen filter, imho your next step is to start taking things apart to see if your flaps are behaving as they should.

be warned however: when i checked my air blend motor i found the stories of easy access were vastly exaggerated. i ended up having to take the top of the dash out to get to the screws holding the blend motor. also i made a mess of the passenger air bag cover (it now sits high).

never did find a problem (my feet were freezing from december onwards! so i just removed all the plastic in the driver foot wells so lots of air comes out - not relevant to your problem but maybe of interest to someone else with cold feet)
 

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1990 300CE-24, 2000 ML55, 2005 CLK320 Cabriolet
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I had the same problem 2 years back in my 2000 ML55. I had to take the dash off and replace the blend motor and there was also another part. Took me like 5 hours with bunch of ziploc bags and I took pictures of what goes where. I would have posted but my computer had crashed, so lost all the pictures. But now everything is OK. I just had to add 1 can of R134 last year after so many years.
 

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Discussion Starter #8
i'm not a fan of the '60s (the decade that is :p ) but i would say that if it is mid 60s (f) you should get mid 60s f air blowing from your vent when the temp control knob is at cold and the ac is off.

does sound like your blend door may be the issue. did you check to see if the air gets warmer as the vehicle warms up? that would be a strong indication.
assuming you cleaned out your pollen filter, imho your next step is to start taking things apart to see if your flaps are behaving as they should.

be warned however: when i checked my air blend motor i found the stories of easy access were vastly exaggerated. i ended up having to take the top of the dash out to get to the screws holding the blend motor. also i made a mess of the passenger air bag cover (it now sits high).

never did find a problem (my feet were freezing from december onwards! so i just removed all the plastic in the driver foot wells so lots of air comes out - not relevant to your problem but maybe of interest to someone else with cold feet)
Yes as the ML warms up the air does get hotter. Is there an instruction on getting the dash out? I've come to a point were I have all the screws out but can't seem to get the dash off. How can you test/tell if the blend door is not working. I am a novice at this so going thru the glove box seems easier but I already have the dash 1/2 way off. Thanks
 

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Discussion Starter #9
Any suggestions. Air conditioner was working fine till I turned the dial to red (hot) this morning, again hot air is coming out with a/c on. This happened last week but a/c eventually came on.
Still looking for dash dismantle instructions to get to the bend door motor. I have gotten all the way to where I can not pull the dash off, stuck at the center by radio cluster. Thnx.
 

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Any suggestions. Air conditioner was working fine till I turned the dial to red (hot) this morning, again hot air is coming out with a/c on. This happened last week but a/c eventually came on.
Still looking for dash dismantle instructions to get to the bend door motor. I have gotten all the way to where I can not pull the dash off, stuck at the center by radio cluster. Thnx.
In post #5 I asked you to explain the circumstances, but you did not answer.

Here are the instructions for removal. It is only necessary to remove the upper portion to replace the Blend Door Motor. There are two screws securing the top section of the radio cluster and two at the bottom. For the bottom ones you have to pull away the lower section to see them.
 

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Here are the instructions for removal. It is only necessary to remove the upper portion to replace the Blend Door Motor. There are two screws securing the top section of the radio cluster and two at the bottom. For the bottom ones you have to pull away the lower section to see them.
43sqd, I am curious if removing the top of the dashboard effects the airbag module?
 

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43sqd, I am curious if removing the top of the dashboard effects the airbag module?
No it does not. The dash and the air bag deployment door are the only thing that comes with removal; the air bag module remains in place..

This is the actual way to do this type of repair (blend door). The proper way saves destruction of the air bag deployment door, dropping screws and not knowing if the repair was done correctly. Everyone seems to favor the easiest and improper way to do things.
 

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1999 ML320 Elegance, BMW R1150RT, SAAB 9-3
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for dash removal the process is simple - work away from 'the inside outward' (radio hole) and the 'outside inwards' (a column interior panels and plastic kick plates...etc) keep removing stuff and looking for hidden fasteners and prying with the wedge till you get off what you need to.

one more thing:

re: "With A/C off or on I am getting gusts of hot air out of the vents and even when I trying to vent in outside air w/ AC off nothing but hot air from vents. Any DIY ideas I can try to fix this problem"

besides the air blend motor another source of problems might be that you have a left over politician hiding inside your dash. did this problem start right after the mid-term elections?? :big laugh:
 

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Discussion Starter #14 (Edited)
Tell us the circumstances of how you started to get heat. Living in Fla. you must have had the controls on A/C for most of the year. Did you touch the control to receive heat and that's when your problem started?
Yes most of the year the temp dial is all the way blue, I think the last time I used the heat was back in 3/10. Problem started when we had a cold night a couple weeks ago and I dialed it to red.
Not here something I've noticed is that when I put it back to blue (cold) heat comes out but over time let's say a day I will get cold air again, strange... So if i get this I have to remove the top of dash as well as the front? No way to access the motor by just taking of the front dash? Also how do you get the woodgrain panel off the front radio/temp cluster this is where I'm stuck at getting the front dash off, sure hate to break or crack it.

Again thanks for all the help here.
 

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Yes most of the year the temp dial is all the way blue, I think the last time I used the heat was back in 3/10. Problem started when we had a cold night a couple weeks ago and I dialed it to red.
Not here something I've noticed is that when I put it back to blue (cold) heat comes out but over time let's say a day I will get cold air again, strange... So if i get this I have to remove the top of dash as well as the front? No way to access the motor by just taking of the front dash?
Also how do you get the woodgrain panel off the front radio/temp cluster this is where I'm stuck at getting the front dash off, sure hate to break or crack it.
Again thanks for all the help here.
Here are the instructions for removal of the wood grain panel. You will also need the special radio removal keys.
 

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Discussion Starter #16
As a side note the dreaded ticking noise started yesterday with the dial all the way blue (cold) but if I move the dial up a little more then a quarter way it stops.
 

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As a side note the dreaded ticking noise started yesterday with the dial all the way blue (cold) but if I move the dial up a little more then a quarter way it stops.
Ticking noise usually comes from A/C box actuators. In your case, most likely blend air motor. 43sqd provided the key documents to you for this weekend project.

Take some pictures during the project and post it here please. This will (a) help you to remember things when installing parts back and (b) other members on this forum to do this in the future.
 

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In post #5 I asked you to explain the circumstances, but you did not answer.

Here are the instructions for removal. It is only necessary to remove the upper portion to replace the Blend Door Motor. There are two screws securing the top section of the radio cluster and two at the bottom. For the bottom ones you have to pull away the lower section to see them.
43sqd,

By bottom ones, are you referring to #9 ? Another question, can the upper dash be popped without removing the instrument panel ? I agree with you that removing the airbag is not the right thing to do.

Thanks
 

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43sqd,

By bottom ones, are you referring to #9 ? Another question, can the upper dash be popped without removing the instrument panel ? I agree with you that removing the airbag is not the right thing to do.

Thanks
I posted the procedure for the upper dash removal earlier this year in the DIY section. It looks like a lot but it isn't. After removing the radio, the glove box and the instrument cluster, it is only a matter of removing screws.

If there are any questions, ask away.

http://www.benzworld.org/forums/w163-m-class/1417771-diy-thread-collection-5.html#post4763314
 

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I posted the procedure for the upper dash removal earlier this year in the DIY section. It looks like a lot but it isn't. After removing the radio, the glove box and the instrument cluster, it is only a matter of removing screws.

If there are any questions, ask away.

http://www.benzworld.org/forums/w163-m-class/1417771-diy-thread-collection-5.html#post4763314
Thanks. I already have the radio removal and pry bars so it should be a matter of knowing where the screws are and prying off the panels. However, removing A pillars and the insulation looks more like a "rip up" job to me. The A pillar instructions in that pdf are vague and hard to follow.
Status update... the N19 is providing the correct voltage +12 to -12 but the ABM does not move. I will try plugging a direct 12V source to the motor when I find a suitable power supply.
 
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