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  #1  
Old 04-28-2008, 02:10 PM
macthomas's Avatar
Mazola Benz
 
Join Date: Oct 2005
Location: Safety Harbor, FL
Posts: 47
climate control 300sdl HELP!

I live in Florida... I need my AC

For a while my fan became intermittent. Especially when I tried to turn it on after I was already running. If I shut the ignition off, turn on the settings I want... then start the car... it worked... sometimes.

Then if I set the temp on "auto" and adjusted the red to blue dial it would work for a while, and then quit. (Added strange thing... when it failed, it would cause a whistling sound on my radio)

Now I can get the fan to come on only if I set it before I start the car and the AC will not come on. The compressor is not coming on. Blows air, heat will work, but no cold air.

Could it just be the push button climate control panel?
Any help would be greatly appreciated!!!


Doops where are you?


thanks
Rick
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Safety Harbor, FL
1987 300SDL 280K
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  #2  
Old 04-28-2008, 10:50 PM
sixto's Avatar
smoke gets in your eyes
 
Join Date: Jun 2000
Location: SF Bay Area
Posts: 19,587
I'd start by checking the fan and compressor separately.

The fan is under the glovebox. Not difficult to get to it. Just providing power to a loose motor doesn't tell you much but check that anyway. Make sure you apply power directly to the motor. Don't mess with the motor regulator, that thing with lots of aluminum posts in the blower housing, unless you know about such things. If there is axial play between the motor shaft and the motor housing, the bearings are probably shot. I'd say time for a new fan or maybe you know enough about motors to replace the bearings. Could also be worn brushes. Replacement brushes are available.

With the engine running and the ACC set to defrost, check for +12V at one of the wires into the low pressure switch at the AC drier. It's the switch with two contact posts, not the switch with two pigtails. If one of the wires shows +12V, the PBU is telling the compressor to engage and the problem is either low refrigerant pressure, a bad pressure switch or something downstream such as the Klima relay.

Sixto
87 300D
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  #3  
Old 04-28-2008, 11:39 PM
Registered User
 
Join Date: Jun 2004
Location: West of Ft. Worth. TX
Posts: 3,934
Someone else reported very intermittent problems and it turned out to be the ignition switch. (In fact, his wife claimed the way to "fix" the problem initially was turn the car off and restart it.) You might try jiggling the switch and see if the symptoms change.

Do you use a large, heavy key ring loaded with keys?
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84 300SD 350K+ miles ( Blue Belle )
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  #4  
Old 04-29-2008, 12:34 AM
AHH,What's up Doc????
 
Join Date: Jul 2006
Posts: 1,212
Quote:
Originally Posted by macthomas View Post
I live in Florida... I need my AC

For a while my fan became intermittent. Especially when I tried to turn it on after I was already running. If I shut the ignition off, turn on the settings I want... then start the car... it worked... sometimes.

Then if I set the temp on "auto" and adjusted the red to blue dial it would work for a while, and then quit. (Added strange thing... when it failed, it would cause a whistling sound on my radio)

Now I can get the fan to come on only if I set it before I start the car and the AC will not come on. The compressor is not coming on. Blows air, heat will work, but no cold air.

Could it just be the push button climate control panel?
Any help would be greatly appreciated!!!


Doops where are you?


thanks
Rick
Your fan motor problem sounds like new brushes in the motor are needed. you could also have problems with intermittent connections in your pushbutton unit (I just replaced mine) and possibly with your Klima as well.
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  #5  
Old 04-29-2008, 01:39 PM
Hit Man X's Avatar
I LOVE BRUNETTES
 
Join Date: Sep 2004
Location: FUNKYTOWN
Posts: 8,908
Thumbs up

Good to see your SDL is running well still, Rick!

This will take a few hours to properly diagnose, but it's worth it.
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  #6  
Old 04-29-2008, 02:26 PM
macthomas's Avatar
Mazola Benz
 
Join Date: Oct 2005
Location: Safety Harbor, FL
Posts: 47
Quote:
Originally Posted by SD Blue View Post
Someone else reported very intermittent problems and it turned out to be the ignition switch. (In fact, his wife claimed the way to "fix" the problem initially was turn the car off and restart it.) You might try jiggling the switch and see if the symptoms change.

Do you use a large, heavy key ring loaded with keys?
Funny you should say that... I was reading a few other discussions and I tried that last night... diddn't work.... I am going to replace the push button ( I am confidant that is bad) and then charge my system/replace orings/dryer/switches... (thanks Hitman ) and go from their.

r
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