<E30> blowers/resistor networks (was: Re: My mechanic is stupid)

[Mark Holbrook <holbrook@xxxxxxxxxxxx>]

SMILLER@domain.elided wrote:
> 
> Hi Mark, welcome to the DIY Heater Blower Motor & Resistor Pack Club!

Thanks, Scott.

For the archives, let me clarify/reiterate the problem and solution:

Heater blower doesn't work on lower settings, but does on max,
indicating an open circuit somewhere in the resistor network that is
used to reduce the current flowing through the motor on the lower
speeds.  The Bentley manual implies that you have to take out the
motor-blower before removing the resistor network.

Wrong!  Plus you stand a good chance of damaging the blowers if you do. 
The resistor network simply unplugs once you get the access panels off.

The resistor board has 3 coiled wires (resistors) and a thermal cutout
on it.  In my case, the thermal cutout failed.  The (first) fix was
easy:  clean out the dirt preventing the contacts from closing with a
piece of paper or fine emory cloth.  If that still doesn't make it work
(check with an ohmmeter - digital or analog, your choice :-) ), you can
bend up the lower (to the board) contact a smidgeon.  The thermal cutout
may now cut out at a higher temperature or maybe not at all, but the
circuit is still protected from meltdown/fire by the fuse, so it's not a
big deal (IMHO).

If that's *not* the problem, you have a loose crimp or stake connection,
as Scott describes.  You can recrimp and/or restake with a pair of
pliers and/or try soldering the connection (but use a 100 watt or so
iron to make sure you put enough heat into it to melt the solder).

God, it's nice to have heat again!

- -- 
Mark (Holbrook@domain.elided)                    "Back roads. Period."
http://www.net1plus.com/users/holbrook/mark.htm

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