workaround for 1993 volvo 850 blower fan motor?

[JimBee]

My trusty (still not too rusty) '93 850 has a blower fan issue. I usually drive this car only during winter, but used it this summer and the blower fan was racing at full speed regardless of ECC settings. I assumed the resistor was the problem, pulled the fuse and am not getting around to looking into it.

So far a new resistor isn't powering the fan. I know I need to pull the fan and put 12 v on it directly to test.

This car starts readily and runs well in winter, so I'll probably keep it going, at least for a while.

Thinking ahead, if there's a problem with the ECC (assuming it will properly direct heat flow , has anybody devised a workaround to direct wire a variable motor speed control.

Seems like boxes are availalbe such as this one:
https://www.ebay.com/sch/i.html?_from=R ... &_osacat=0

What might be the simplest way to do this? Any thoughts or suggestions?

[misha]

Check the codes for climate system.
Your '93 have diagnostic ports under the hood.
Port B1 is for climate system.

Instructions are in MVS database.

Or here:
https://volvoforums.com/forum/volvo-850 ... nit-62413/

[JimBee]

Unfortunately, the under hood AB socket block is kind of crusty and isn't usable, so I'm kind of stuck with the old fashioned way: checking the blower and and plugs.

[misha]

Don't let the blower decieve you.
It will always work when hotwired(wired directly).
The problem is that it could pull more power than it should from power stage and ecc will shut it down in order to protect power stage and ecc unit.

Ac/rec orange lights will flash for around 20 sec everytime ignition is turned on and blower is on to inform you that there is a fault and dtc stored.

[JimBee]

Oh yeah, I had noticed the blinking orange lights before the blower started revving full blast. Thanks for the tip. Maybe it's time to replace the blower motor.
Good to know that there's built in protection of sensitive circuits.

[erikv11]

Flashing CC lights doesn't tell you it's the blower motor, it tells you there is a DTC stored. You still have to find out what the fault is. Bad damper motors etc. will also make the CC flash.

[abscate]

I’ve got a couple of spare motors if junkyards are skinny , Jim

Are blowers 1992-2000 compatible?

[scot850]

There was a change along the way on blower motors. Can't recall what year. I need to check as I think I used to have an older 850 one, but it may just be bad memory!

Just checked Abscate's friends at FCP Euro. The fans are listed with different part numbers for 850's up to 97 (all years):

https://www.fcpeuro.com/Volvo-parts/850 ... =4530&v=83

to the 98- cars have 2 part numbers but it looks like a part number change:

https://www.fcpeuro.com/Volvo-parts/V70 ... &d=55&v=91

Neil.

[misha]

Also...check temperature sensors under the roof handles...driver's & passenger side.
They have a little blowers inside and they should spin for a second or two everytime ignition is turned on and should spin all the time when blower is turned on.
They could be jammed or bad because of lint build up from dust since they are pulling cabin air through them.

Other than that....high speed blower could mean two things....bad power stage or bad ecc unit.

Bad ecc unit is more common.

[misha]

...pulled the fuse and am not getting around to looking into it.
So far a new resistor isn't powering the fan.

I guess that you put the fuse back.