850 Blower Motor

Hi-

I recently (~3 weeks ago) purchased a 1993 Volvo 850 GLT with ~120k
miles on it. About a week later, I smelled and saw smoke coming from
the vents, and the blower motor ceased to work. Lights on the ECU have
been flashing. Car does have ECC.

Diagnostic codes showed shorts on the damper motors (all of them), no
power on the temperature sensors, and no signal from blower motor power
supply.

My intuition (and intensive Google searching) indicated that it was
probably just the blower motor, but perhaps also the power supply, so I
ordered both.

After pulling apart the glove box, knee guard, etc., I was finally able
to get the blower assembly out. I connected the motor straight to the
battery and it didn't turn, while the new one did.

Replaced the motor, reconnected all the cables.

Start the car up, no go. Blower motor doesn't turn, still have flashing
lights, still have error codes about inlet fans being seized or
shorted.

Tried replacing the power supply, that didn't change it either.

Any ideas? I really don't want to have to take it to the dealer
(inconvenience and cost).

Thanks,

Noah

 

Noah,
Just going with the basics here - when the old motor seized, perhaps a
fuse blew. Apparantly there is lack of power to the blower.

 

Also, check to make sure the connector didn't fry at the motor.

 

Don't want to assume but did you check your:

[1] Fuses
[2] Ballast Resistor

 

I vote for a bad blower motor resistor module- It is to the left of the
blower motor in the duct work, held in by a few torx screws. follow the
wires back from the motor to the module. Runs about $60 online. I don't
know how to test it.

 

As I mentioned in the first post, I replaced the resistor module with a
new one, and it still does not work.

Fuses are all fine as well.

 

....no, you didn't mention...please check your post again

 

If you call the resistor module a power supply-OK. But I don't think of
it that way. The other thing that happens is the capacitors in
the ECC control module- the rectangular box in the dash with knobs on it
for settings and temp selection LEAK and short the board. This sudden
death is witnessed as masses of white smoke coming out of the dash as
the printed circuits within the module fry. That is $750 +, and the ECC
module was changed after 1993. A salvage yard might have one for
$150-200 .Clearly an expensive gamble to try replacing it. Mechanically
it is easy. Remove radio and pop it from below by releasing some push
tabs and maybe a screww in back. It unplugs from the harnesses easily. I
nursed my 93 850 for years.The 94 and on ECC module is different and I
don't think it will work. If you open the case of the ECC you can smell
the burn and see the burns around the black and silver capacitors on the
circuit board. Make sure you have your radio code before you remove it.
Good Luck.

 

If you call the resistor module a power supply-OK. But I don't think of
it that way. The other thing that happens is the capacitors in
the ECC control module- the rectangular box in the dash with knobs on it
for settings and temp selection LEAK and short the board. This sudden
death is witnessed as masses of white smoke coming out of the dash as
the printed circuits within the module fry. That is $750 +, and the ECC
module was changed after 1993. A salvage yard might have one for
$150-200 .Clearly an expensive gamble to try replacing it. Mechanically
it is easy. Remove radio and pop it from below by releasing some push
tabs and maybe a screw in back. It unplugs from the harnesses easily. I
nursed my 93 850 for years.The 94 and on ECC module is different and I
don't think it will work. If you open the case of the ECC you can smell
the burn and see the burns around the black and silver capacitors on the
circuit board. Make sure you have your radio code before you remove it.
Good Luck.

 

Many times multiple strange electrical problems on 850s mean that the
electrical portion of the ignition switch is failing. I don't know if
that is your situation, but given the high failure rate of these things
then changing the original one on a '93 would at least be good
preventative maintenance and might fix some of your problems.

John