Finally got my blower regulator in. AGAIN!
 

Ok guys.

For the SECOND TIME in 6 years, I put in another blower regulator. God, too much work changing that.

My blower fan speeds suddenly went from low or automatic to blowing on high all the time. The last regulator was a "quality" MB OEM replacement, got it from Rusty at the time, $250 part. I mean..... this does not look like some technological achievement that should be THAT expensive, especially if it doesn't last that long. We're talking 2 feet of wires, a piece of porcupine metal prongs, and a transistor.

Though I don't recommend buying anything from China if you can at all help it, this time, I bought what is probably a China made one (perish the thought!) for $43, delivered to my door, off ebay. It'll be interesting to see how long this lasts, maybe I'll get a full 30 days out of it before it fails, and have to do the job all over again, or maybe I'll get lucky and it'll last 6 years!

1991 300d, 180k

Yes, keep us posted. On my 92 300D I'm on the original regulator with 245k miles. Blower motor replaced once at 150k. Occasionally makes minor squeaks, but basically in good shape.

91 300D needed motor replaced at 104k. But so far no regulator with either one.

Yep I replaced one on a friends 300E. It was not a fun job.

Ive got 263K on my original unit. The fan is starting to chirp at low speed. Eventually will need replaced but its very faint so it can wait another day.

I am curious though if there is a correlation between fan motor failure and regulator failure...at least on the original MB part.

One mechanic told me to replace both at the same time
 

One mechanic told me if you're replacing either the regulator or the blower motor, to do them at the same time even if one is fine. He said in the case of my regulator, the reason it only lasted 100k was maybe because I put in a new regulator but not a new motor at the time, then the regulator is responsible for turning an older motor that doesn't spin as freely as a new one.

Certainly makes some sense that it's possible.

New blower regulator makes fan blow a slight bit faster
 

I've always felt the Mercedes fan on low, was too low. It needed to be about 15% more blowing effort to prevent me from having to switch to a higher fan speed.

Well I guess I got my wish. This Chinese (I'm assuming it's from China anyways) regulator is set just that 10-15% higher blower speed than my 2 previous regulators. The drawback now is that I can hear the fan blowing on low. Prior to that, I wouldn't hear it when on low.

Oh well. At least it's working properly.

In my 190E I had some low air flow problems as well. However it turned out to be a clogged up evaporator. I blew off a thick coating of years and years of junk... Even on low the air flow is nice, even and plenty. Sadly the 300D's evaporator is not nearly as accessible as the 190E's.