Armed with Art Benstein's excellent guide and the help of a friend I spent a long day replacing the blower motor and switch (some notes below). When I took the old motor out and tested it, it worked fine. Put in the new motor anyway -- the old one was known to be the original. The old resistor pack looked better than the aftermarket replacement, so kept the old one when it tested fine. Put everything back together and... still no working blower motor! Checked fuse again, tested good, replaced anyway, no difference.

Also the instrument panel and console lights stopped working, except for the light in the small clock, which I put in along with a tach, replacing the big clock. It lights up fine, controlled by the rheostat to the left of the instrument panel. Everything else: darkness. Hmmm.

Suggestions welcome. :)

- Matt

'91 245, 170k ('90 780t 216k let go this weekend.. sad, but to a good home!)



Notes on blower motor replacement:

- Art Benstein's page (cleanflametrap.com) is, as noted, for an older 240. For a '91 like mine, replace all instances of "Philips" by "Torx", except for the screws that hold the glovebox in. In a few cases, you'll need a slimline Torx bit with a long thin shaft to get at the recessed bolts in the drivers side knee pad, and the center console.

- I didn't find it necessary to remove the left side vents. It was enough to loosen them and pull them to the side, allowing the outer distribution casing (on either side of the blower motor housing) to be removed. The right vent was tightly wedged in against a large silver module, to me unknown (ECU?) so I didn't dare remove it first. Doing so would have made removal a lot easier.

- Do not drop the screws that hold the motor while still in the motor housing, because they will end up under the heater core and be difficult to retrieve!

- My replacement motor was a VDO part made in Canada (ordered from FCP Groton). Confusingly its wires come out in the opposite, "up" orientation from the original motor: this caused me to initially mount the new motor the wrong way round (with the wires pointing down, just like they did in the original). If you do this the impeller shafts will be offset and things won't fit back together.

- There is a flexible piece meant to go over some of the sharp edges inside (I think) the center console somewhere. This is the only part I had left over after putting everything (else) back together. I guess this is supposed to prevent wire chafing, so it's worth paying attention to where it goes.

Searching the archives some more to try and figure out what is going on, I noticed someone mentioned the cigar lighter in the center console has two connections. I found it impossible to connect the second (small) wire, so I left it off, but surely this cannot explain any of the symptoms (all dash and console illumination out except small clock)..?

Thanks for the suggestions. I went back in today, reconnected the cigar lighter wire, ground to bare metal the area around the 4-way ground connection on the upper right mount point of the console frame, as well as the ground point I created for the blower motor on the lower console frame bolt on the transmission housing. Blower motor now works!

Also replaced the two instrument panel bulbs ($10 each from IPD -- WTF?) and they now work!

However... console lighting and "roof lights" are still out. No voltage at the roof lights. I tried looking at my Bentley wire diagrams, but I can't figure out where the ground point for these is supposed to be. Any ideas?

That could be it exactly. Does that small wire ground the console lights? Probably. Sounds like a ground issue anyway. Make sure everything is grounded correctly.

I kinda agree it is likely to be a grounding problem.

The best way to track this is with a test light. With all the conditions correct for blower operation, trace the voltage with a test light to the back of the speed selector switch. The white/black wire brings the battery from the fuse. The red wire (you just replaced) takes it to the motor. The motor is grounded behind the heater unit where you can't see, to a piece of sheet metal -- the same one the heater control valve is attached to -- and then ultimately through its mounting screw to the floor and firewall.

If you use your test light to poke through the motor's ground wire insulation, testing there, and you see light, you've confirmed it just needs a good ground.

On the blower motor replacement page, if you go to the bottom, you'll find a link to a a heater core replacement on a 91 sedan, with a few pics of behind the console, the cigar lighter wiring, the motor ground wiring, and yes, that silver box (cruise control) was in the way too.
--
Art Benstein near Baltimore

"Much later, when I was discussing cosmological problems
with Einstein, he remarked that the introduction
of the cosmological term was the biggest blunder he ever
made in his life." -George Gamow