300te 4matic AC issues
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Joined: Mar 2004
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From: upstate new york
2002 E320 4Matic Wagon
300te 4matic AC issues
Hi all,
I am pulling my hair out with my AC.
The compressor cuts out and the electric fans come on high when I select the bi-level [double arrow] or defrost button. High side pressure does not jump above normal range.
It does not seem to do it on normal setting [one down arrow]
I began this odyssey with the compressor cutting out randomly and only reengaging upon restart.
My pressures seem normal,at 2k rpm 30-35 low side and 225-250 high side
I have
bypassed the evap temp sensor by inserting a 10k ohm resistor in the socket
jumpered the two pressure switches on the drier[fan is on low speed continuos]
replaced the temperature sensor coolant [blue body,top of head]
replaced the panel control unit [twice,each were rebuilds and supplier sent a second when first did not solve problem]
replaced monovalve
cleaned condensor and compressor clutch [neither particularly dirty]
I have not addressed the compressor speed sensor beyond wiggling connections
I believe it must be related to the temp sensor coolant as fans high and compressor cutout are controlled here when engine temp spikes [my car runs constantly at 80 to 85 C,measured at gauge and with radar? non contact thermometer]
The manual only talks about vacuum activated changes in flaps when switching to bilevel or defrost.
My car has no KLima relay,controlled by MAS.
Does the temp sensor coolant signal go through the panel control unit?could I have two defective panels? BTW i disconnected my aux coolant pump before replacing panel
Anyone have any ideas? Thanks in advance
I am pulling my hair out with my AC.
The compressor cuts out and the electric fans come on high when I select the bi-level [double arrow] or defrost button. High side pressure does not jump above normal range.
It does not seem to do it on normal setting [one down arrow]
I began this odyssey with the compressor cutting out randomly and only reengaging upon restart.
My pressures seem normal,at 2k rpm 30-35 low side and 225-250 high side
I have
bypassed the evap temp sensor by inserting a 10k ohm resistor in the socket
jumpered the two pressure switches on the drier[fan is on low speed continuos]
replaced the temperature sensor coolant [blue body,top of head]
replaced the panel control unit [twice,each were rebuilds and supplier sent a second when first did not solve problem]
replaced monovalve
cleaned condensor and compressor clutch [neither particularly dirty]
I have not addressed the compressor speed sensor beyond wiggling connections
I believe it must be related to the temp sensor coolant as fans high and compressor cutout are controlled here when engine temp spikes [my car runs constantly at 80 to 85 C,measured at gauge and with radar? non contact thermometer]
The manual only talks about vacuum activated changes in flaps when switching to bilevel or defrost.
My car has no KLima relay,controlled by MAS.
Does the temp sensor coolant signal go through the panel control unit?could I have two defective panels? BTW i disconnected my aux coolant pump before replacing panel
Anyone have any ideas? Thanks in advance
