Blower Motor?

My new to me '80 300TD's blower motor doesn't seem to work. I tried wiggling the key (I read that in a previous post), and I also checked and wiggled the fuse. Pressing the different buttons on the Climate control unit seem to change where the air is diverted, but heat just kind of seeps out the vent. The faster I drive, the faster it seems.

Where do I start looking?

[Ohtooman]

You might try giving the blower motor a good whack on the bottom with a rubber mallet. If it is getting worn out, that can start it working again. There is a wealth of information on this forum on fixing a worn motor if this is the problem. The search feature on this forum helped me when I had the same problem.

That some warm air is coming when you are moving, and that it comes from differing places is the good news. That probably means you won't need to work on the monovalve or the ACC stuff.
What you have is most likely worn brushes inside the electrical blower motor, as Ohtooman suggests.
If they are worn, and the 'whack' gets it going, it will fail again shortly. Cheapest fix is to remove the blower motor from under the right side and then you can pry apart the ends and get to the electrical brushes. If you are not familiar with them, they look like small blocks off soft metal and are pushed into the end of the stator with springs.
You can find replacements at hardware stores. Almost all replacements need some filing or grinding to ge them to fit back into the channels they slide in. Be sure to use a good temp controlled solering iron to reattach the wires.
Not a hard job. Good luck.

I went out and taped on the blower motor. With the car off, but the key on, the motor works on the defrost setting, but its speed cycles up and down. It turns off on any of the other settings.

Should I still suspect the brushes?

That makes the call a little tougher, as it could also have a problem with the monovalve or the ACC switches. That being said that when you tapped it, the thing started to blow at all is a very strong indication you found the problem.
Did you say new to me? The heating and AC system on these old diesels will not last as long as the rest of the car. Needs attention at this age. It is possible that there is more than one problem here, but you most likely have an electrical motor with worn brushes.
As a note the defrost setting supplies the highest voltage to the blower. That the blower does not work on the other settings may just be consistant with worn brushes and a weak old electrical. It cost me about three hours to figure out how to do it and to fit the new brushes in there. Still not hard to do. ACE Hardware should have the parts you need. Just disasemble slowly, and made notes on what goes where. Ir you cannot get it fixed? A new one is available here for around two hundred, give or take...

After I let it run a little on defrost, all the other settings worked. Tepping the blower motor changed its speed. The brushes must be making a very poor connection.
I suspect that on the defrost setting, the motor gets full power. On all of the other settings the motor's juice is run through resistors. I think that initially, it took full power to make the motor run.

see...

Fixed for $6.03

Sounds like your problem. After I did this a couple of people posted that the blower motor in their cars were of a type that you could not service. Guess there are two brands out there. What I fixed was about as easy of a repair you can get. Took longer to walk to the 4 blocks to the hardware store and find brushes than to do the fix. This was on a weekend when the starter rebuilders and fan supply stores were closed. They would also be a good place to find this size brush.

Where exactly is the access to the blower motor on an 81 300SD?

The Chilton Manual says something "Remove the cover under the right side of the instrument panel." Under the steering column is a big panel that comes off, I saw nothing that looked like a motor up there. Or do they mean the climate control panel?

Any help would be appreciated. The repair seems simple enough, if I can just find the blower motor!

This is a USA issue car right? Steering on this side of the pond is on the LEFT hand side of the car

Regardless of which side the steering is on, and I'm pretty sure this Chilton Manual is the USA edition, the "cover under the right side of the instrument panel" is still cryptic to me. This is not like a Jaguar where there are actually fuse doors under the dash.

Someone who has replaced the blower motor must know where it is and how to get to it! Thanks!

[JimSmith]

markluta,

I just did this on the 1982 240D, and on that car it was under the passenger side dash board, just inboard and forward from the glove box. I know it says "instrument panel" in your manual but I think the W126 is similar to the W123 in the placement of this device.

Good luck, Jim

Jim is right, (so is this Jim but I run under a different name ) anyway this motor is under the passenger side dash board section. Three (I think) screws hold the entire fan assembly in the blower box. Take these out, pull out the wiring harness from the fan assembly then you will see how to get to the brushes IF you have serviceable brushes. You will have to bend two little tabs up with a small screwdriver to pull the brushes out. They are soldered to the motor so I cut the wires flush with the old brushes since I had no idea what the new ones would look like. The new brushes had very long wires connected that WOULD have made it to the solder points on the motor but still it is easier to solder two wires together than to de-solder the old connections and there is no guarantee you will find brushes with very long connections. I live in Florida where we have tons of fan stores with actual parts, also most hardware (old time stores, NOT Lowes or Home Depot) will have a box of various size brushes. The two above stores I mentioned sent me to the paint section when I asked for brushes and had NO IDEA what a brush in a motor was , go figure. Anyway AFTER I did this job I remembered the alternator/starter rebuilders in the area and thought to myself that they would have them as well. Get close if you can't find an exact match. Very easy to file to size if need be. I didn't have to as I found the same number as the brush I needed but others have had to file to fit. It's carbon and files like butter so this is not an issue if what you find is a little big.