AC blows hot on drivers side cold on passenger side
#77
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2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
Yes! This confirms that that the duo-valve controls the return flow from the heater, so one must be open incorrectly when in cooling mode.
A question for ssfisher: has the car always had this fault since you got it?
If so - maybe the hose connections are wrong, but, electrical more plausible otherwise.
A question for ssfisher: has the car always had this fault since you got it?
If so - maybe the hose connections are wrong, but, electrical more plausible otherwise.
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2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
we need the electrical schematic for your cars HCVA system to find out the relay location on which SAM. As far as I know the control panel only communicates via CAN bus.
#82
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Are you holding the REST with key on #2? I don't understand why you don't have 30-31
#84
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2001 s500 with amg factory sport package (black)
The duo valve i removed from the car i just tested on the bench. Each coil has 21.5 ohms resistance and each coil operates when power is applied
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2001 s500 with amg factory sport package (black)
Yes, both sides block air with power on the coils. So since the one on the bench and the replacement one in the car both did not close one side, it is telling me its not the valve.
#87
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Yeah sounds like you have a control issue.
They click shut right? As soon as you apply power it's closed? That explains your voltage readings, they are PWM solenoids, so the low voltage one is trying to stay mostly open, it's barely pulsing the power on so you're getting <3v on that side.
Gotta be a control unit or temp sensor issue. I'd think if there was a shorted temp sensor you'd be getting error codes for it, the only way it would run heat with the controls set to "LO" should be if there's a controller fault, as on that setting it should be max cooling regardless of internal temperature settings.
They click shut right? As soon as you apply power it's closed? That explains your voltage readings, they are PWM solenoids, so the low voltage one is trying to stay mostly open, it's barely pulsing the power on so you're getting <3v on that side.
Gotta be a control unit or temp sensor issue. I'd think if there was a shorted temp sensor you'd be getting error codes for it, the only way it would run heat with the controls set to "LO" should be if there's a controller fault, as on that setting it should be max cooling regardless of internal temperature settings.
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2001 s500 with amg factory sport package (black)
Yes, it shuts as soon as power is applied. I swapped the two temp sensors left to right and still had the same issue on the same side. I dont have another control unit to plug in and try. Does anyone know if i can test the one in the car somehow if i put it on the bench?
#89
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Originally Posted by ssfisher
I swapped the two temp sensors left to right and still had the same issue on the same side.
NR.30 and NR.31 are those heat exchanger readings.
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2001 s500 with amg factory sport package (black)
Which ones did i swap then? The onez i swapped are located behind the radio. They are a two wire plug and very small.
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Yea, we swapped cables and the high reading went from NR.03 to NR.04 so that tells us the sensors are good because the high temp went from left to right.
#94
I know this thread is old but I was wondering if the OP has eventually found a solution to the issue. I am having the exact same problem, the heater blows very hot regardless of the temperature setting except when in LO mode. The duovalve has been replaced, did not have any effect. So far I have not been able to find a report of anyone resolving this issue on any of the forums. Would appreciate any suggestions. Thanks!
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2001 s500 with amg factory sport package (black)
As of now it's still broke. We never found the issue. It still drives me crazy. I have been using a plastic hose clamp on the hose that stays hot. I clamp it when it's hot out and in clamp it when it's cold. Mostly it has been clamped for the last few months as I live in Colorado. There was alot of good troubleshooting and suggestions made by several people and I checked and tried all of them but we never have found the problem and I stopped looking into it. I wouldn't mind starting up again to resolve it tho..
#96
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Originally Posted by evenfall
I know this thread is old but I was wondering if the OP has eventually found a solution to the issue. I am having the exact same problem, the heater blows very hot regardless of the temperature setting except when in LO mode!
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I guess his issue is different than mine. Mine blows hot always, no matter what setting. I believe your correct in saying it's the temp sensor if it works on LO. Wish mine was that easy
#98
Sorry I must have missed that the OP issue is that it blows hot at all times. It is not as much problem for me during the warm season since I can always set it to LO and everything functions as it should on that setting. Thanks for the tip about the temp sensor! I will pursue that direction. I also posted on the w220 UK forum and that thread had an issue identical to mine where it works fine on LO, no definite resolution there. Thanks again.
#99
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No problems. I got the 04 S430 few years ago and I didn't know that it was a problem until someone pointed that out for me. I opened it up and saw the broken wire right away. Re-soldered and it has been working fine since.
If you go through the voltage diagnostics you will see 0 readings for the open circuit. The climate system see 0 so it try to compensate with heat.
If you go through the voltage diagnostics you will see 0 readings for the open circuit. The climate system see 0 so it try to compensate with heat.
#100
Is part number 2108300072 correct for the cabin temperature sensor? It is part #14 in this diagram:
https://www.oediscountparts.com/medi.../5/5891070.gif
does not look like it is in the ceiling assembly or is it the same part in both? This is all I've been able to find after searching multiple vendor sites.
https://www.oediscountparts.com/medi.../5/5891070.gif
does not look like it is in the ceiling assembly or is it the same part in both? This is all I've been able to find after searching multiple vendor sites.