'93 850 heater fan works on 4, not on 1, 2 or 3!

For a while now, the heater fan on my '93 850 SE 2.0 20v saloon has
been playing up. Half the time it would work fine, then for the rest
would generate a quite loud noise when rotating. Not a squeak, more of
a roar! Sometimes, it would swap between these quiet and loud modes at
random moments (accompanied by a loud clunk when it did so).

Then two weeks ago, the fan stopped working altogether on settings 1,
2 and 3 but DOES still rotate on setting 4 -- but now the roaring
noise is there permanently.

Following advice given elsewhere in this group, I've just changed the
associated relay, but to no avail.

So what now? The switch? The fan itself? I've checked all the
connections and they appear to be in order.

Another post suggest changing the associated resistor, but I'm having
difficulty locating it. On later models it appears to be underneath
the relay, but doesn't appear to be so on my car! Any ideas?

TIA,

Stu C

 

You've burned out that resistor, it drops voltage to the motor on speeds
1-3, and is not used on speed 4 where the motor gets full voltage. And
you need a heater motor to take care of the clunking and roaring. The
resistor is a "home plate" shaped thing with a 4 pin plug in the heater
box right beside the heater motor.

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Thanks for the info. Both resistor and motor replaced (the latter a
breaker's yard unit), and now all is dandy.

Removing the old motor, I did find a large piece (3" x 3" x 1") of a
stiff foam-like material lying in the space where the fan was, that
had obviously broken off from somewhere. Maybe it was this that had
been doing all the clunking? Just a thought.

Cheers,

Stu C