E.C.C resitor bypass?
 

So may fan is gone for sure..or is it? This is a two part question.

How can I test the fan and resistor, or at least what numbers should I be seeing at the resistor if its working properly?

If the resistor is blown, is there a way to get something cheaper than the $200+ ones I'm finding online? A home rebuild perhaps?

Basically the drain got plugged and was leaking water everywhere into the passenger floor. Once I got this fixed my wife thought the way to fix the "musty" smell was to spray a highly concentrated bleach mixture into the vents and down the cabin intake under the hood. --this is what happens when you have an incredibly inquisitive and helpful wife--this was done to "save" me the extra work. Shortly after the fan stopped working all together. Its been about 2 months and I'm just getting to it.

Any advice, would be greatly appreciated.

Cheers
-Scott

You can remove the connector with the larger Blue and Black wires from the power stage (blower resistor) and use a jumper wire to test the blower itself. If you short out those wires the blower should come on at full speed and not make any other squeaks or "bad bearing" noises.

If you pass that test then there is a DIY fix floating around for the power stage itself that involves taking the heat sink off and replacing the MOSFET transistor. The original MOSFET is apparently unavailable but there are others that will more or less work. If you are good at soldering I would say that you can do this yourself. I am good at soldering but I (knock on wood) have not yet had one fail.

...Lee

you can go to the volvo dealer and buy one new for 150.00 and not have to pay for shipping..... That is for the resistor

VICTORY!..kind of
 

So thanks to the many useful tips found within this forum I have managed to save myself a bunch of cash.

Lee:

I got the whole thing apart and check the ECC modual...mint, not the tiniest hint of burn out. Blower motor covered in corrosion and rust. I removed the blower motor stripped it down to the motor it self and didn't stop there. I opened it up and pulled the central shaft and cleaned everything with W/D and a brass wisk.

Assembled everything and had a shiny new looking motor, reinstalled it and the moment of truth was starting the car and turning on the fan. works like a charm, fired up without hesitation.

So I'm thinking victory, time for a cold one. No sooner did i finish that the wife comes home and informs me that it's not blowing as hard as it used to. I have to admit, grudgingly, that it isn't blowing terribly strong. I pulled the motor and ran it while holding it, seems to have plenty of power. But when I put if back in the second time, it still doesn't seem to be coming out of the vents very strong. just spinning it by hand it seems to spin with some friction and stop pretty quickly. I lubed both bearings with axle grease.

So I guess the question is; is this motor just tired and needs to be replaced? The last thing I want to do is burn up the ECC contol, which is at least $200 everywhere I can find one.

Lee, any thoughts?

Tough call.

The blower motor and the power stage are about the same money. Putting a new power stage in front of a bad blower will just blow the power stage itself - again.

What I have done that has been successful with the blower motor is to lube the bearings and then, using a battery charger to make it run, reverse polarity on the motor to get it to run in both directions - back and forth several times until it quit squawking.

You do need to remove the blower so that you can get to the front bearing which is always the one that causes problems it seems. Even then it is tough to get to the bearing unless you remove the squirrel cage.

Axle grease is way to heavy IMHO. I actually used WD-40 since I had a can in the garage and I am a couple of years deep afterwards with no problems. These are just brass bearings and not ball bearings.

You should be able get blower motors and or power stages in the $125.00 range from online vendors but the wallet pain factor remains high.

...Lee

Problem solved
 

So I ended up just ordering a new bosch motor. Took the cage and mounting plate off the old one, plugged it all back in and it's working like a charm. Blowing very strong, hell it blew out a ton of dust and leave debris everywhere.

Lee, I don't have the cabin air filter on the car. There is a box around the opening but it has sort of a funnel top, looks like it's supposed to seat To the balck plastic cover above and keep out some crap. Can I just get the filter and drop it in or will I have to find the "proper" box?

In any case, thanks for the advice, a/c is a beautiful thing down here in Durham, just in time for the hurricane.

Cheers
Scott

For anyone looking here is a blower motor complete for 100$.

Volvo 850 Blower Motor at 1AAuto.com

The cabin air filter retrofit requires a new frame to replace the original that looks kinda like a funnel. They cost around $15.00 from either a dealer or on eBay. Installation is just plug and play - take the old one off, set the new one on, and then install the filter itself. Other than the torx screws to get the cowl cover off there are no tools involved.

The cabin air filter goes a long way toward saving the evaporator coil on the AC since it prevents tree crud from clogging it up and then retaining the moisture and corroding the evaporator coil itself.

...Lee