Working on a 87 300 sdl. Blower motor started to squeal or screech on low and auto (mostly when auto is near low, when on high or auto is high no squel). Seems to be emanating from the blower motor box, however I can hear the noise in the vent system as well. Took out blower motor cleaned it and oiled it with tranny fluid. Put it back in, it still squealed or screeched on low and low auto. Replaced blower motor with a new one. Still does the same. Do have a few problems with climate control unit and have a new one ordered. However, I am wondering if the squealing is related to Blower regulator or something else in or near blower box. Maybe even the bottom cover of the blower box. Can't see any scratches from blower motor shaft on bottom cover. When radio (new radio) is on am and fan starts, radio screechs.

 

Wow! This is very interesting. I own a 97 S420 and just before the blower quit working, I heard a squealing noise while the setting was on low. Then the blower action became intermittant. Then it blew when it wanted to blow. Then, there was nothing at all. I am now awaiting the arrival of a new blower motor, and I'm wondering how to remove the fan from the motor? How did you do it?

As for the secondary squealing that you are experiencing, at the moment I am without an answer. But I am hoping that the motor replacement does the trick with my issue.

There is a such thing of receiving a bad part though. I would suggest that you return the most recent motor for an exchange, just to rule out the possibility of it being the motor. And should you do this, be sure to mark it in some manner to insure that you don't receive the same one back again! Just me being sketical is all.

As for the regulator, it's an electrical and from which I don't see it being able to make any noise, unless it's burning. Then it would be a sizzle and the smell of burning wire.

I'm going to check and see if there is a secondary motor of some sort that could be behind the glovebox or in the dash, and get back to you.

 

If you removed the motor could you not run it on the bench to ensure it runs without noise and that there is not undue "sparking" from the brushes.

Where did you lubricate it?
Were the brushes in good order?
Are the elctrical connections tight? The fact that the radio is "picking up the noise" means that it must be "spark" induced radio frequency (RF) so my suspect would be the brushes. However the rotor may be on the way out..bad segment etc.

 

Found out that this model a others does have squeek problems when the blower regulator (its also called a procupine in these models) is out. Many people swear it sounds like blower motor is shot, only to find out it is procupine (regulator).

 

check out my replay to first replay to original. These regulators make squeals when then go out. Many swear it is blower motor. I did check original blower motor on bench, it did not make noise. I am sure that the new blower motor is fine. Got a super deal on new motor, so I probably will keep it.

 

Subsequent to my last post in response to yours, I received my new blower motor. I took a punch and a hammer and banged the motor stem out from the squirrel cage. Simple! It came out fine. And I banged the squirrel cage right onto the new blower motor, and it went on fine. I cleaned up the housing and re-installed it, and it runs beautifully. Gets nice and cold in the cockpit.

However, I did look at the regulator. I still don't see what there is about the regulator that could possibly create any noise. I'm baffled on that one![&:] Oh well, just insure that the squirrel cage is seated correctly and not hitting against anything, and you should be fine. Best to you.

 

Here is what I found out. The regulator was not making the noise. It was the motor. However, I [we] believe that the regulator is causing feed back into the motor. Remember I have two motors, a new one and the old one. Both make the same noise, both are quiet on the bench. The reason we think it feedback into the motor on low and low and medium auto is because the current is being fed through the regulator at those speeds. At high it is not regulated. If we are right, this is what happens to a bad or cheap speed control switch on a ceiling fan. When this happens on a ceiling fan the motor hums. That what we think is going on and will know for sure when the new regulator comes.

Bart Ward

 

Bart,

I am inclined to disagree, and here's why; you've stated that it hums. Now, while I am not an electrician by trade, I do suspect some other issues you may want to consider.

1.) There are some clips on the squirrel cage that look like staples. I believe these to be balancing weights I am not for sure, but I noticed that they are strategically placed. Be sure that they are in place.

2.) The regulator that we keep referring to, may not be grounded like it should. Check to be sure that you got enough of that paste where it should be. This is what I'm really hearing could very well be the matter.

3.) Be sure all of your connections are tight and that your wires are not touching, and are insulated.

4.) Check that squirrel cage one more time to be sure that it's not touching anything.

5.) Make sure all of your contacts are clean.

The reason I'm listing all of these things is because that's what I was sure to do, myself. My reinstallation went very well, and everything is working beautifully.

Oh, I also applied the di-electric grease to all of the electrical contacts.

I believe this helped me, and it may very well help you. I hope this information is useful, and if not...chuck it.

Peace.

 

After another round of frustration it looks like you hit it on the nose. I took all blower and climate control wires and plugs apart and greased them with di-electric. Check and cleaned all grounded wires. It looks like the grease on the blower regulator wires were the most important to us grease on. Put all back together and the noise in the blower motor went away.

 

Good for you, Bart and Ellen. Glad to hear that your frustrations...at least in this area has ended.