W115/W114 heater blower motor DIY (PURISTS BEWARE)

[mabbonizio]

The heater blower motor in my 72 220D hadn't worked since I purchased the car.
Being as it came from texas - I presume the previous owner didn't care too much.
It does get pretty chilly in PA and since I plan to use this car year round, to keep my much nicer W123 out of winters wrath I had to get the heat operational.

For those of you who don't know, the heater blower motor is buried at the most interior part of the dash. The entire car was literally built around it, and for a show quality vehicle I would have certainly dismantled the entire interior and put up the $$ for the correct part.

For this daily driver / winter beater / fun but a bit crusty old car that wasn't an option. At this point, if you're a a purist who thinks every crusty W115 should be restored to the highest standards - you should probably stop reading.

Step 1
Remove the windshield cowl. The wipers come off easily by removing the (2) 13mm bolts. Then the small plastic caps under them are removed, as well as the larger (can't remember the size) slim nuts under the plastic caps.

There are some plastic rivets on the front of the cowl that are removed by pushing the center in and pulling them out.

Step 2
Remove the cowl and screen and set them aside.
You're then looking at a water deflector. - sorry i forgot to snap pics of this part.

Its pretty infuriating Mercedes didn't make this a removable panel, so one could lubricate the heater blower motor.
I literally cut this panel out, carefully - with a variety of dremel / sawzall tools and blades.

Step 3
Once removed I then had full access to the heater blower motor. It is bolted in from the front (inside the car) and so I carefully trimmed away all the plastic shroud to be able to extract it from the car.

At that point you've got something like this:


Step 4
I then measured the opening and checked out fans on amazon. I know others have used computer fans - but i wanted something I thought could withstand the elements and provide some strong air flow. I settled on this "pusher" radiator fan off amazon. For around $20 there wasn't much to lose.

I wired the fan exactly as the previous fan was wired, just two wires that go from the fan speed control module to the fan itself.




Step 5
I then drilled two small holes and used the mounting hardware in the kit to secure the fan. There isn't much space in there for it really wiggle around - so I think zip ties work just fine here.







I then tested it and was pleasantly surprised by the air flow on all settings. It's a bit weaker than my W123 blower motor - but it's much better than nothing.

Friday I am planning to cut a rain deflector from a junk car and bolt / rivet it into place. I could probably also just bend some metal to get it to fit. Unfortunately I discarded the rain guard I cut out of the car. I also plan to treat and paint the surface rusted metal that was exposed by removing the rain guard.

[Mike D]

Not pretty but it sure beats frostbite!