seems that my ac works fine blowing cold air just does not blow hard enough to feel. It registers on the fan as high but never blows more than the third bar out of ten. Is there a way I can get into the fan unit and fix or do I need a new fan motor?

More than likely your problem lies in the blower motor regulator. They are notorious for going bad. Although I would wait for several opinions on it. I just replaced my E-55's with one from an S car and with a little modification it works like a charm. Mine would work halfway sometimes and other times It wouldn't work at all.

I agree with SSWEET55. It sounds like your blower current regulator has quit working properly. These units have been updated several times. It's a very easy replacement on an S class car.

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Mercedes Benz Master Tech - Retired

Just like 99' 500, I had AC problems. Traced it to the regulator through voltage checks. I ordered a S-car regulator through Phil and got everything hooked up and the blower sitting still was working fine yesterday. I drove the car today and like the 500 car my Contol unit shows to be blowing on max but I have very little air movement out the vents (This is with the car running going down the road). It doesn't matter if it's on Automatic or manual. So I thought maybe the regulator is overheating or something. But then when I stopped the car and put the ignition in the 2 position (engine off) the blower works like a champ...you can change it manually from low to max and the blower works really well....I need help! Would it be a power feed wire from the ignition? I thought I had helped a fellow forum member but I have the same problem.

Is this problem on the 1999 S-class?? if so then the electronic blower regulator that mounts to the blower motor is the MOST likely cause, good luck!

MBD, I was going to send you a PM but it was too long so I'll just answer you here. The blower and current regulator are mounted to the top of the heater housing and are accessible from the engine compartment. Just forward of the windshield is a big black panel that covers the blower and the cabin filter. There are 6 screws that hold the panel on, 5 on the right side and 1 on the left. Once the screws are out you can lift the panel up part way and disconnect a temp sensor and a heater hose thermostat from the underside on the left side. On the right side there is a vacuum element to remove the plastic line from. Once the panel is removed you will see the cabin filter on the right side. The blower is under the filter and the current regulator is mounted to the blower motor. When removing the regulator be sure to unplug the black plug to the regulator before the wires to the blower motor. Use care installing the new regulator and don't overtighten the screws securing it to the blower. You can test the blower by just removing the blue wire from the blower motor and connect a grounded wire to the connection on the blower, it should run on high speed. The best place to buy the part is from Phil at The Fast Lane portion of this web site. Hope this helps,Robert.

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Mercedes Benz Master Tech - Retired