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Climate control inop no blower motor but can hear the compressor kick on
Help I have no lights on climate control but if I hit the auto or turn the fan speed on I can hear the compressor turn off and on ?
0 lights checked fuse 23 and it’s hot ? Can a bad blower regulator backfeed cause this controller not to light up ?
Thinking controller or shorted blower regulator since compressor is kicking on and off ? But 0 lights on the controller ! TIA
The compressor is a variable displacement design and doesn't have the typical on/off clutch. It adjusts displacement as required for cooling. If you think it is operating, see if one tube is warming up and one is cooling down.
F23 also runs the aux. water pump, so you might want to try unplugging it. The blower supply power comes from on the the front prefuses and the regulator just gets a speed signal from the AAC control, so a bad blower or regulator really shouldn't affect the control. This is really one area where a scan tool is invaluable. Get an inexpensive Mercedes specific tool and diagnose it instead of guessing and throwing parts at it. Everything in that system is expensive.
I put the scan tool on it and I can see voltage from the controller to the fan motor going up as I turn the fan speed higher but 0 lights no fan speed I have this code and checked a lot of fuses
Well if you look all the codes it seems the rear Sam is screwing up the can bus circuit yo ther modules ! I liked at ac data stream and when you play with the controller it show on data like the blower speed going higher when you turn the fan speed dial higher … the ac compressor turn of and on but no lights at all the blower motor is barely spinning and making a squeaking noise so I am starting to feel they there are multiple issues with this car , probably from moisture ruining the rear Sam ! The passenger door module is not working now too ( window movement on door opening and closing ) and I did window reset
Do the passenger side windows work with the switches? If so, you probably have an issue with the door open switch or, maybe more likely, the rear SAM reading the switch. The AAC module runs a pretty extensive self check. Are all of the blend doors responding? AAC control power is from driver's SAM, rear SAM could be tied in for roof position (A/C control changes based on roof being open or closed), but it shouldn't completely shut it down. Are you getting power to the regulator?
I habe NO power to blower motor but the blower motor spins very low speed with key on crazy the bearing is squeaking lol so I will replace it .
definitely thinking the rear sam
went bad from moisture : I changed one years ago in early S class that got wet ..,
is the rear Sam vin coded ? I don’t think
the last one was ? Thanks
I was going to buy a used one in good condition .
Last edited by globalauto; 05-29-2024 at 11:32 AM.
No VIN coding on the SAMs. The do have some variant coding, but nothing I can think of off the top of my head that would be that critical on the rear SAM. If your scanner has the option to transfer coding from the current one, that would be the safe option, but you can probably get by with just plug-and-play.
Looks bad, but it would probably clean up. The SAM is sealed pretty good, so it might not have any internal damage. I would also pull the roof module connectors that are just below the SAM and clean those and also pull apart and clean the CAN hub, which is where all of the brown & brown/red wires go to. Your fuse/relay box looks ok as far as I can tell. If you get blue corrosion there, it is pretty much trashed because of all the internal connections you can't get to. The fronts are much worse for that because they are oriented with the relay sockets up and can take on water all the way through.
Thanks so much for answering , the roof module is ok I had cut some retainer 6mm bolts , obviously it’s been getting water in here for some time . I told owner SL s don’t like staying outside in the rain ! Such as life .. keep you posted by the way this the 3rd ram I have replaced in this car , think before it’s all done the rest will need to be done . Or the owner sells the car . Got to love German job security 😂
Replaced rear Sam connector cleaned everything up ! Still getting voltage code air can bus voltage . I hand power to back of the plug and ground , but 0 lights no controls . Any idea where the Maxi F1 m2 and F2 m3 fuse is located ?
Thinking the rear Sam smoked the controller ?
Last edited by globalauto; 06-05-2024 at 09:34 PM.
05-21-2024, 09:20 PM
