I'll chime in :)

My '78 and my '88 ACC systems perform the same and on each when they died, the defrost did not jump-start it. Replacing the motor solved the problem. On the '78 it died slowly so defrost worked for a few weeks. On the '88 It just up and died.

From what you described, you have the exact same symptoms I had. I would HIGHLY suspect the motor. Replacing the brushes may work, but replacing the part is enough a trial of patience for me :)

Good Luck!

Scott

Thanks Ron & Scott. I'm going to pick up a meter this weekend and check to see if the fan is getting power. I noticed last night on the way home that setting the temp to high heat was definitely bringing some heat into the car. And, as I've said, I can hear the engine react when turn on the A/C so the pushbutton unit seems to be working to some degree although I suppose just the fan controls could be out.

Bill

sounds more like the fan to me.
If you feel warm and cold then you can rule out monovavle and temp wheel. lets us know what you find

This thread was excellent!
 

Thanks for answering my dilemma with 94 E320 blower fan not working. As noted, 80K miles , 5-6-years operation, I need new brushes. I have 168K. I will remove hood, climate intake screens, windshield wiper assembly and hope to find the blower fan sitting there. My thought is to remove it and take to an electrical motor shop and have them put in new brushes. It's Sunday night, coming up on Presidents Day, and happy to find all you guys at the forum.

take a look, not hard to replace brushes on the older fans, newer may be a bit different but I doubt it.
You may have to order brushes, not a common item at most electrical fix it shops

Update
 

I picked up a used fan w/cage from someone here on the forum.
It's turning but with little power.

The old fan definitely wasn't working. You could tell even by spinning
it by hand. Jim, the guy I got the fan from tested it before sending it
to me. While doing the passenger seat straddle, I checked it out on low
before installing it and it powered up.

However, although it seems to be turning, it's very weak and the fan
controls have no effect on it. When I go through the PBU, I can hear
the compressor kick in when go to A/C and it I can feel hot air when I
spin the temperature wheel to hot. It doesn't seem to get particularly
cold when doing the reverse but there is a difference.

When I stop and turn the motor off but leave the key in the acc position,
I can just hear the fan spinning. And it does so if the PBU is in the off
position. Turning the key all the way off stops it.

During a test drive, I seemed to be getting more air through the defrost
than any other setting but at nowhere approaching the speed it used to
blow at.

Both fuses are Ok.

Any ideas?

Bill

May be fan regulator, but if fan brushes are worn it will spin slow as well. The only thing that does not make sense is the fan turning with ACC off. To the best of my knowledge It should not. May have a short or regulator issue, what year again? I may have one lying around

It's an `88 560 SEL. The guy I bought from has another one if I want
to try it. Is the fan regulator the part the fan plugs into?

Thanks,

Bill

I believe, at least on mine, that the blower control is silver (aluminum) and the temp regulator is black.
Have you tried to run 12V directly to fan?
Does it spin well, if so then the blower (fan) regulator is probably toast. It simply (yea right) puts resistance in the circut.
I will tell you they do not often fail so r/o the fan
I know you are having fun, ACC gremlins are the B_ _ _ _ :D

Well, before pulling the fan out, I hooked the old one up directly to the
battery to make sure it was dead. And it fired right up blowing leaves all over the driveway.

I looked it up on Fastlane and found a picture of the Regulator. It's here:
http://img.eautopartscatalog.com/live/R202261960BEH.JPG. Mine's silver but otherwise the same. Not cheap, either.

I emailed the guy I bought the fan from to see if he's got the regulator. You said you might have one lying around. Would it fit my `88?

And, yeah, I'm having fun. I can't wait to hang upside down again on the passenger seat. At least I've got sheepskins on it. :)

Thanks,

Bill

sorry the one I have will not work on your model.
give Ken Redmond a call I believe you can find his name and number or email here http://www.benz-store.com/about_us.html or
http://www.benz-store.com/contact_us.html
He is very knowledgeable and deals in used (good) elctronics. Also review your symtoms with him, he may have another idea. He has really helped me in the past, is reasonable and fair.
Let us know what you decide to do

Ron,

Thanks. I spoke to Ken and he felt like it was the regulator
not the climate control unit. I mentioned that my old fan didn't
turn easily by hand but did fire up when hooked directly to the
battery.

If I understood him correctly, a bad fan pulling the wrong voltage
can damage the regulator. When I told him I'd bought a used fan,
he suggested that I buy a new motor instead ($105 w/o the cage).
The used fan could end up causing the same problem. He said usually
for that repair, both the fan and regulator are swapped out at the
same time.

He's got used regulators that have been tested for $135 versus
$350 for a new one. The used one comes with a warranty.

So $240 solves my problem. It probably would have cost me
$800 just for parts had I gone to my regular shop. I'll let you
know how it turns out.

Thanks again!

Bill

Great, Ken is a gem
When you replace the cage, make sure you do not knock any of the small weights off the fan
good luck

I picked up a used regulator for $50 from someone here on the forum. It arrived today and I installed it. I was very happy to hear that fan spinning at multiple speeds when I first hooked it up. Looks like the blower regulator definitely needed to be replaced.

I'm going to call Ken now and replace the used blower I bought with a new one. Ken pointed out that it's usually an older fan that messes up the regulator.

However, all problems are not solved. Air is not blowing out of the center vents. The side vents seem to work but the majority of the air is coming from the defrost vents. The controls work for on/off on the side vents and I can see a control moving inside the center vents when I adjust them but no air.

The low, high and auto settings on the fan are all working now, which wasn't the case before replacing the regulator. The temp wheel seems to be working fine, too.

Any ideas as to what I need to do next to get air to the center vents?

Thanks,

Bill

Just want to add that I just took it for a test drive. Cycling from
full cool on the temp wheel to full heat had no effect on the center
vents, most of the air is coming from the windshield vents on economy
or any of the regular air settings.

I get cool air from the side vents but not the center. And I don't get
heat from the floor vents at all regardless of settings.

Bill