Question about 2007 Mercedes-Benz ML320 CDI
SOURCE: 2003 Mercedes Benz E500
There is a valve that is located between engine and firewall. I fixed it myself with help from benzworld.org. It seems to be a common problem with this model and the new valve has a slightly different part number and is supposed to be better. It took about 1 hr. you have to take a few parts off to get to the valve, but if you can handle basic tools, it should be ok. there are great step by step pics on the benz site. part is about $40 at dealer. good luck!
Posted on Jan 25, 2009
You have one of two possible problems.
1) The temperature shaft retention nut is loose behind the knob
2.) The wires to the potentiometer part of the temperature may be broken.
Either one is common to this vehicle. The replacement of the AC controller is about 900 dollars. If the wires are broken, they can easily be reattached to the circuit board via soldering. What you would have to do is remove the control box from the dash, and disassemble it. Once the unit is apart, there are 3 wires from the temp knob to the circuit board that need to be re-soldered. The unit CAN be repaired, as opposed to the expense of replacing it.
Posted on Apr 23, 2009
Hello I'm a M.B. tech. 1st you need to know why the freon is low. Hopefully it just needs to be serviced. There is a component located in the lf of the engine compartment called a receiver drier. It soaks up the moisture in the freon so the gases can work the way they are supposed to. On this unit there should be 2 switches(I believe they were combined into one switch in 98. 1 switch is a temp switch that operates your electric fans, the other is a compressor cutoff switch. Assuming the compressor is not coming on-take a fused wire and bridge the 2 contacts- If the compressor does not come on at all there is another problem(it is not low on freon. On the condenser there is a high side port(it is the bigger of the 2)By the brake master Cyl.(lf of the engine compartment thereshould be a smaller low side valve in line with the fuel cooler hose. Usually you can hook up a machine to the low port and **** freon in through that port. Assuming you do not have a refrigerant machine. It is very self explanatory on the bottle of r 134a refrigerant which can be purchased at your local auto supply store. I would start with 1 lbs. and add dye with the freon in case there is a big leak. If the system is overcharged it will not cool properly. I believe the system capacity is approx. 2 lbs. Add a few ounces after the first pound until a/c system is cooling properly and the electric fans are also coming on when the system gets to high. If you get a can with a good Gage set on it you should see the high side between 150 and 2000 psi(fan coming on at max. press.) also the low side should read about 35. It is about the temp of the evaporator which is i=located in the dash and the blower blows through this component out through the vents. Hopefully I have been helpful.
Posted on May 28, 2009
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