190E A/C Fan Speed - PeachParts Mercedes-Benz Forum

#1 03-10-2003, 02:01 AM

1993 190E A/C, Defrost and Heater Air Duct fan speed increases but air isn't blowing at the proper volume. Just bought the car and not sure how long it's been doing it. Have a friend with the same model which air duct blowing velocity is much higher. You can hear the fan speed increase when changing the switch, but the volume of air only increases slightly. Cooling temp is fine.

It seems as if the ducts are restricted.
Is there a filter which may be clogged?

Thanks in advance for your help!

Potomac Pat · #2 03-10-2003, 08:41 AM

THere is no filter for the H/VAC system in the (W201).

Maybe check for restrictions & to see if the duct work is snapped together correctly.

MTI · #3 03-10-2003, 02:36 PM

Take Pat's advise. Remove the underdash panel, start on the side that the airflow is the weakest, and check for dislodged ducting. The MB ducts are blackflexible plastic, much like a clothes dryer duct and are pressure/snap fit onto the vents and the center console air source. Have a good flashlight and perhaps someone with small hands (tight space) to help you out.

#4 03-10-2003, 06:10 PM

Thanks for you advise. I have the right side underdash out. Will check the left if it will let me further in. The restriction seems to be at the fan source. All ducts are affected. Not sure how to access the fan source. The fan speed is definitely increasing but the air velocity is being restricted. I'm trying to find either an object restriction or duct disconnection or crack or hole. Still searching. I'll let you know what and or if I find the cause. Please let me know if you can add any other advise.

Thanks again for you help.
Bill

#5 03-13-2003, 12:55 PM

I haven't found the source of the obstruction. Does anyone have any suggestions? everything is clear to the fan. I haven't pulled out the dash. Not sure if thats necessary.

Thanks again,

Bill

#6 03-13-2003, 12:57 PM

Check and make sure the squirrel cage fan is tight on the fan motor shaft. If it is loose you will get little air movement while the motor turns fast.

sbourg · #7 03-13-2003, 02:54 PM

I offer this as a remote possibility, but as the saying goes - no matter how unlikely, if it's the only possibility left, it's the right one.

I had a squirrel cage blower in aftermarket air in a Chevy van with the same symptoms. I simply didn't end up using the air much, but repaired it after the fan blade disintegrated while it was on once. What I found is that the incorrect blade for the cage had been installed, and the motor was wired in reverse in an attempt to correct. Fan blades are usually designed with 'right-hand' and 'left-hand' versions, depending on the direction of flow in the squirrel cage housing. I replaced the blade with the correct version, reconnected the motor for opposite rotation, and the fan now blows like a banshee, and the velocity increases with the motor speed.

What may have happened is at some time in the past, the blower was serviced with new parts, and assembled incorrectly. The blade vanes should be oriented and move such that they scoop the air from the central region and push it through the housing in the direction of the outlet. For example, if the blades were installed on the wrong ends of the motor shaft, or the whole assembly were inverted, or any combination - you would probably get the symptoms you have.

Steve

MTI · #8 03-13-2003, 03:56 PM

By the way, the blower motor is accessed from the engine compartment side, not the dash.

#9 03-17-2003, 01:52 PM

Is the blower fan difficult to access?

thanks,

Bill