sdreaden

2003 e500 - 4 zone climate control. AC blows cold when it blows at all. In manual or Auto mode, the AC sporatically stops blows air altogether. If I press the AC off button, no change. Sometimes it starts blowing again after a couple of minutes and other times it will not start blowing again for 30 minutes. Also, it may be coincidental, but it seems to only stop blowing if it is fairly hot outside. Last week was fairly mild weather and it did not happen at all. I tried changing the blower regulator out but it did not fix the problem. Maybe a dumb question, but is their more than one blower motor? (i.e. under passenger dash) Are their additional fuses or relays that may be faulty? Does anybody have any other suggestions or troubleshooting tactics?

Also, I have seen the article on checking the AC values on the Ebenz site but the section regarding getting Error codes does not seem to apply to the 4 zone controls. Does anyone know how to check for error codes to see if some sensor is malfunctioning?

Thanks in advance!

Barry45RPM

When your A/C demands maximum blower power, such as in DEF, ar MAX cooling upon startup when it is trying to cool the car down rapidly, there is a blower motor regulator which cuts out, randomly stopping your blower motor from operating. Well known problem which was "solved" by MB with a revised blower regulator part. It is located somewhere under the dash right (Passenger) side.

I personally feel that the revised part doesn't permit as much high RPM and therefore CFM from the blower motor, but, that's only my impression. Do a search here.

sdreaden

Thanks for taking the time to reply. I replaced the blower motor regulator with an OE replacement from Autohaus but it did not fix the problem.

I have also noticed that the interior lights get brighter when I rev the motor and dimmer when the motor returns to lower rpm. Is this expected behavior or possibly another symptom of the problem which is causing my AC blower motor to stop.

Is it possible that one of the batteries or battery control modules is going bad and causing the blower motor to shut off when the current is low??

Any ideas welcome...

Barry45RPM

It is possible, though unlikely (this late in the game) that the blower regulator you got is one of the old part numbers. ...and no, I have not noticed my lights dimming based on fan speed.Maybe the blower is drawing too much current.

ShowRoom Auto

2003 Mercedes E500 Sport. My Cabin Blower Is Not Running. AC is On, I can Hear the Exterior Cooling Fan Kick On When I Turn The AC On. Where Is The Fuse & Relay # & Location. I'm Missing My Fuse Diagrams. Does Someone Have A Fuse Diagram Picture I Can See? I've Recently Replaced The Alternator. And Moved The Location Of The Battery Control Module Due To Retarded Engineers Having The Ground Located Where Water Fills Up The Body Where GROUND BOLT IS.