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Discussion Starter #1
have a 97 E320 the duo control valve replaced last year.
New fan motor with the S-class swap done 5 years ago. Blows hard and cold like a meat locker.
a/c compressor leaks a little ( I add freon once every 2 years).

problem: it blows like a tornado at stop and idle. as soon as I step on the gas, it barely blows still blows cold. but barely comes out.
as soon as I take my foot off gas it blows hard again. I leave the fan speed at just shy of high. never touch it.
any help would be greatly appreciated.
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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7,215 Posts
Hello :)

Do you mean the blower airflow capacity is reduced , or airflow comes out of different vents like the defrost under the windshield, so less air comes from the center vents ?
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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7,215 Posts
You can check the output from the controller to the regulator to see if it stays constant. If it does, it is something to do with the blower regulator .

STAR TekInfo

check item 10 that it stays constant with manual blower setting (not in AUTO mode).
 

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E250 Bluetec Sprinter250 Bluetec
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Isn't it blowing on windshield when you say no flow from the vents?
If that's so, you gotta leak.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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4,343 Posts
Check the vacuum line in front of the coffin box in the engine bay. That is for the AC, it uses the intake manifold vacuum. If the vacuum is broken or otherwise not functional, you will get wacky AC under full throttle.
 

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W163 and General M Gremlin
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W163 and General M Gremlin
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thats a lot of wires in there. Where do I start ? what do I do? =/
You're not to be looking into the box...
Deplore said,
Check the vacuum line in front of the coffin box in the engine bay. That is for the AC, it uses the intake manifold vacuum. If the vacuum is broken or otherwise not functional, you will get wacky AC under full throttle.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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2644214


Follow the yellow vacuum line. It terminates to a flexible vacuum line to the back of the intake manifold.
 

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Discussion Starter #14
how do i got about checking it. and thank you for the clarification Khomer2. Am i looking for like a kink or something?
 

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W163 and General M Gremlin
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how do i got about checking it. and thank you for the clarification Khomer2. Am i looking for like a kink or something?
You found it via Deplore’s post ok?

Check to see it (yellow line) is continuous and unbroken, to a flexible vacuum line in the back of the intake manifold. The vacuum line too, should be intact and unbroken- overtime with engine compartment heat, these too go brittle and break. Inspect carefully back there.
 

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Discussion Starter #16
gave it a good look just now. gently flexed everything but all the lines are wrapped up in that insulation so couldnt really see if any lines were torn or anything. I listened carefully for any hissing didnt really hear anything ;/
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Follow the yellow line that I drew up. The other end comes out into a vacuum line toward the engine.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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How about the other end? Did you find it?
 
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