Engine fan issues!!!
03-03-2017, 07:47 PM
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2004 S500 4Matic
03-03-2017, 07:49 PM
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03-03-2017, 07:55 PM
#8
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You need a scanner that can see the desired fan percentage, like Star or similar. If you see the fan desired % go up and the fan doesn't move, the issue is in the fan itself. If it isn't, check the temp sensor and the a/c pressure sensor, although if they were out you'd have other problems.
If the fan isn't coming on when the M/E asks it to, either there's no power on the large wires coming in, or the small data wires coming in aren't sending signals to the controller. Or the controller is bad, or the motor is bad, but you said you replaced those.
If the fan isn't coming on when the M/E asks it to, either there's no power on the large wires coming in, or the small data wires coming in aren't sending signals to the controller. Or the controller is bad, or the motor is bad, but you said you replaced those.
03-03-2017, 07:56 PM
#9
MBWorld Fanatic!
FWIW I had fan issues on my first CL and it was cheaper to replace the entire fan assembly than to mess around with just a controller or motor, the replacement procedure is a bit of a PITA on the 600 cars though.
03-03-2017, 09:02 PM
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You need a scanner that can see the desired fan percentage, like Star or similar. If you see the fan desired % go up and the fan doesn't move, the issue is in the fan itself. If it isn't, check the temp sensor and the a/c pressure sensor, although if they were out you'd have other problems.
If the fan isn't coming on when the M/E asks it to, either there's no power on the large wires coming in, or the small data wires coming in aren't sending signals to the controller. Or the controller is bad, or the motor is bad, but you said you replaced those.
If the fan isn't coming on when the M/E asks it to, either there's no power on the large wires coming in, or the small data wires coming in aren't sending signals to the controller. Or the controller is bad, or the motor is bad, but you said you replaced those.
03-04-2017, 11:06 AM
#11
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M/E is Motor Electronics, what MB calls the engine computer. I'd have to look at the specific diagram for your car but most of the fan systems have the desired fan signal sent from the engine computer to the fan controller, then the controller sends the voltage to the fan to get the desired speed.
03-04-2017, 05:15 PM
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2004 S500 4Matic
M/E is Motor Electronics, what MB calls the engine computer. I'd have to look at the specific diagram for your car but most of the fan systems have the desired fan signal sent from the engine computer to the fan controller, then the controller sends the voltage to the fan to get the desired speed.
03-05-2017, 06:57 PM
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Update
I noticed that the compressor wasn't coming on, so I checked the refrigerant and low and behold it was low. I then added 24oz and the compressor switched on as well as the fan...
I will keep you guys posted!!!
I will keep you guys posted!!!
03-06-2017, 12:16 PM
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03-07-2017, 10:34 AM
#17
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The AC is one of the factors that control fan operation. Whether the AC is on or off, or even works, should not affect how the engine temperature controls fan operation.
03-18-2017, 06:04 AM
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w203 c320
I have a 2004 S320 cdi that fan comes on when ignition is switched on and blows like 747 on take off.It switches off when ignition is off.Does the fan get controlled by a SAM or ecm
the diagnostic on engine shows no fault codes but shows fan is on 90% operation. it has a 648.960 motor
the diagnostic on engine shows no fault codes but shows fan is on 90% operation. it has a 648.960 motor
03-19-2017, 02:10 AM
#19
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I had a fan problem on a 928..didn't even know it till I got stuck in a traffic jam. They were seized up...one barely turned...the other not at all. Have you tried seeing if they spin freely by hand? I found used ones from a California junk yard for $350 for both...the dealer wanted $750 a piece.
