560SL blower motor runs hi only

[dsutton01]

I've noticed recently that my climate control blower doesn't seem to push any air on low speed like it used to. I removed the cover under the hood today to check it out and here's what i found:

If i turn on the system with the high speed button selected, it runs great. If i switch it to low without turning it off, it slows down, but continues to spin. there is no noticeable airflow from the cabin vents, however.

If I turn on the system with the low speed button selected, it usually doesn't even start turning, though occasionally, it will spin up to the low setting, which, like i said, results in no noticeable airflow from the cabin

Under the hood, attached to the firewall on the passeneger side, very close to what I *think* is the hot water valve, there's a small motor spinning (i can hear it), visibile only through what looks like a ilttle transfer section from the motor to another part. What is this piece, and why is it spinning all the time when the climate control system is on?

Any ideas why my motor's low speed is so low now? Do i need a new motor?

Thanks.

[Pierre560sl]

Hum,
Did you look for a blower motor RESISTOR?

[dsutton01]

no, where would i find it? What would i look for when i fnid it?

[Walrus]

Originally Posted by dsutton01

Under the hood, attached to the firewall on the passeneger side, very close to what I *think* is the hot water valve, there's a small motor spinning (i can hear it), visibile only through what looks like a ilttle transfer section from the motor to another part. What is this piece, and why is it spinning all the time when the climate control system is on?

Any ideas why my motor's low speed is so low now? Do i need a new motor?

Thanks.

The little motor you describe, next to the monovalve is your aux water pump. It runs when heat is demanded from the system, and circulates the hot water thru your heat exchanger in the heater plenum box. As to your fan, I suspect your blower controller is kaput (I'd have to consult my manual to offer any other suggestions...).

From your post, I also suspect you do not have a comprehensive manual. I would highly recommend you obtain one before going any further... It is possible to short out your climate control system controller, which will be a rather expensive repair.

[Pierre560sl]

Originally Posted by dsutton01

no, where would i find it? What would i look for when i fnid it?

Sorry, I would not know were it is located on your car. Most likely on the firewall or if you remove the glove box door you may have an acces to it.
The good thing about the resistor is that you could visualy see if it is burned.
Usualy, the thinest coiled wire (The lo speed of the fan) burns first.

[AF300E]

If i'm correct, you have the sort of laterally mounted climate control panel with one temperature wheel and then a series of buttons in the middle and the fan hi/lo on the right (same as w126 chassis)?
If so, you might find the control unit in the dash has dry solder joints. I had the same issue, pulled the control unit, resoldered everything, replaced it and found it fixed a whole lot of probs (made the temp wheel more accurate, the vacuum pods started working proberly etc).
Costs nothing, may fix your problem if you can't see anything amiss with the resistor.

[dsutton01]

yeah, that's what I have. I removed the panel from the car and am attempting to take it apart, but i can't seem to figure it out, and i don't want to break it. Does anyone have a page from the manual that shows how to disassemble it?

Thanks.

Originally Posted by AF300E

If i'm correct, you have the sort of laterally mounted climate control panel with one temperature wheel and then a series of buttons in the middle and the fan hi/lo on the right (same as w126 chassis)?
If so, you might find the control unit in the dash has dry solder joints. I had the same issue, pulled the control unit, resoldered everything, replaced it and found it fixed a whole lot of probs (made the temp wheel more accurate, the vacuum pods started working proberly etc).
Costs nothing, may fix your problem if you can't see anything amiss with the resistor.