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I got my 2000 ML430 about a year ago and have not had any issues. The previous owner was elderly and had only put about 60k miles on it when I purchased it. The vehicle now has 75k miles.
It is starting to get hot in the PNW and I noticed the other day that my AC was blowing warm air. I checked on here and saw that people usually replace fuse 44 when the aux fans are not working and are good to go. My fuse 44 was blown. I replaced fuse 44 and nothing happened. I also checked K26 and that was good as well. My AC clutch is working. I checked the freon level and it said it was empty. I added freon until the gauge said it was at the top of an "acceptable" level. The air got a little cooler, but it was not a significant difference. I also pulled my glove box off and checked the flap actuator and that was working and moving as I changed my air from hot to cold.
I am out of ideas.
I read about every post online that I could find. One guy said he kept adding freon and eventually the aux fans engaged. I am afraid to overpressurize the system because of possible damage. I have also read posts about upgrading the wiring harness, but I am not sure if that will help at this point, although I am open to the idea.
If anyone has any experience or ideas please shoot them my way! I appreciate any insight and help!
Last edited by Chadmc56; Jul 20, 2020 at 07:59 PM.
Reason: updating vehicle year
As for the dual fans not coming on, they will not come on until coolant temp. & AC pressure rise to a certain degree.
I believe that you have a problem with the Blend Door Motor. Remove the glove box and move the lever to the other side and see if you get cold air. If you do, you will have to replace the BDM which requires removing of the Inst. Panel.
As for the dual fans not coming on, they will not come on until coolant temp. & AC pressure rise to a certain degree.
I believe that you have a problem with the Blend Door Motor. Remove the glove box and move the lever to the other side and see if you get cold air. If you do, you will have to replace the BDM which requires removing of the Inst. Panel.
I checked that yesterday and it seemed to be operating as normal (movement wise). I will manually push it today and see if there is any change.
Why didn't you advise everyone what you have done instead of us suggesting things to check?
Are you saying that it moves from one side to the other when you switch from heat to AC?
I did say I had “checked the flap actuator” which is the name I found that part under online. I believe on Mercedes Medic.
And yes it does move side to side on its own when switching from hot to cold, however I am not sure if it is performing at 100% because I just verified it was moving and never physically moved it.
After you replaced the fuse, did you check it again to see if it was blown?
hi Maj Dundee guru, I've been trying to fix my overheating problem due to dual fans are not working.
1. The relay K26 has 12 volts on 86 and 30.
I don't know who puts the ground signal on 85 to activate it, however I put a jumper wire between 30 and 87 and the fans moves but the jumper wire hots.
2. A/C is working good I think, it cool and the blower is working also.
3. I already replaced the control confort module and the problem remains
Do you have any idea why when I jump the dual fans act relay to send 12v to the fans it becomes very hot? Is there any other relay or switch between that could be grounding the 12V?
I had to take my 2000 ml430 to the shop and they told me that my compressor was turning but it was not putting out enough pressure. You wanna make sure you get the gauges and fully charge the system and look at the high side and low side of the system. I had to pay 300$ just for the diag.
QUOTE=Chadmc56;8111857]Hi everyone,
I got my 2000 ML430 about a year ago and have not had any issues. The previous owner was elderly and had only put about 60k miles on it when I purchased it. The vehicle now has 75k miles.
It is starting to get hot in the PNW and I noticed the other day that my AC was blowing warm air. I checked on here and saw that people usually replace fuse 44 when the aux fans are not working and are good to go. My fuse 44 was blown. I replaced fuse 44 and nothing happened. I also checked K26 and that was good as well. My AC clutch is working. I checked the freon level and it said it was empty. I added freon until the gauge said it was at the top of an "acceptable" level. The air got a little cooler, but it was not a significant difference. I also pulled my glove box off and checked the flap actuator and that was working and moving as I changed my air from hot to cold.
I am out of ideas.
I read about every post online that I could find. One guy said he kept adding freon and eventually the aux fans engaged. I am afraid to overpressurize the system because of possible damage. I have also read posts about upgrading the wiring harness, but I am not sure if that will help at this point, although I am open to the idea.
If anyone has any experience or ideas please shoot them my way! I appreciate any insight and help![/QUOTE]
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