850 Heater Fan, ECC & Power Stage
 

I need information about the Power Stage between the ECC and the Heater/AC fan in my '93 850. The original (1993) ECC failed was replaced with a newer version (9166550) a few years ago, which required some rewiring (271927). I recently noticed that the fan is running much slower than the fan in my '96 850. In my '93 850 with fan set for maximum speed, I measured 4 volts across output of power stage and 7 volts across fan motor.
Q1. Should the fan go to full speed using the original '93 power stage and the newer ECC?
Q2. If I replace the power stage what part number should it be?

Hi Lewmer and welcome to the site.

I'm not sure but I didn't know the '93's had ECC. So your temp dials show temperatures or just progressive lines?

My flatmates 93 GLT has ECC, but manual windows?? Which I kind of found a bit bizarre. It also has a manual drivers mirror, and electric passenger one, although there are 2 power mirror switches in front of the window switches. According to his manual this was normal :\

So Howdy everyone … I have a 94 950 turbo W/ECC, heres the short/short version of problem first off i pulled codes and I know I have a few issues W/ actuators etc , codes I got were 231,233,511 …not too bad since when I got the car it had no dash …It seemed to be blowing hot air and would function enuff to get by , but now what happens is … Start car blower runs full speed or wherever I place speed switch …after about 5? min blower quits m no screetching no noise ,just quits… If I shut car off fire it up and it does same thing , everytime I restart motor blows great then quits …Anybody got any tips 1 thanxz in advance !

update...Recently I tried this with the key in position II... the blower seemed to NOT kick off, W/ engine not running , Ign. on ...

You have a bad electronic resister. Pull the fan and make sure it's not partially seized also.

Robert ? ... Any ideas on what might be going on here ...Is there some sort of self resetting breaker/relay that could do this ?
I posted this on another site , that is why it addresses everyone below ...thanxz for all that you have helped me ... I am VOLVO 4 EVER !
So Howdy everyone … I have a 94 950 turbo W/ECC, here's the short/short version of problem first off i pulled codes and I know I have a few issues W/ actuators etc , codes I got were 231,233,511 …not too bad since when I got the car it had no dash …It seemed to be blowing hot air and would function enuff to get by , but now what happens is … Start car blower runs full speed or wherever I place speed switch …after about 5? min blower quits m no screeching no noise ,just quits… If I shut car off fire it up and it does same thing , everytime I restart motor blows great then quits …Anybody got any tips 1 thanxz in advance !

update...Recently I tried this with the key in position II... the blower seemed to NOT kick off, W/ engine not running , Ign. on ...

I apologize Everyone if this is double posted ,or out of place...
Anyway thanxz for the reply hoonk!
Herse the problem / W/ some of that theory , ...When I shut the car down ,and immediately restart it the blower comes on full blast, or where ever I place the rheostat ? control...and what I found last nite tentatively ,testing not conclusive ,but... If I don't start the car ,and turn ign. to pos. II the blower works ,and didn't ? kick off . I need to time test everything to make absolutely sure,however ... Meanwhile ,back at the Ranch-ette ...It's colder than a Wenches Teet in a Brass Bra up here , so if there is any way to " Jumper ' or hot wire the blower ? for now until I can find an overpriced resistor ? if thats the case , I would consider that option ...

Will the resistor from a MCC car work ?

No, the manual climate car resister is not electronic. The MCC resister reduces the voltage to control the speed. The ECC resister provides a variable ground to the motor - so I guess you could make a 10 gauge jumper wire, connect it to the ground lead at the fan motor and the body. Terminal 1b/black wire at the resister is the ground - or fan motor. That will make the fan run at full speed all the time.

https://cimg7.ibsrv.net/gimg/volvofo...298b6ff0e2.jpg
https://cimg8.ibsrv.net/gimg/volvofo...2b55a48233.jpg

Thanks again ...but why would it work all the time W/ ign on pos.II ,if it in fact does , I need to test it further ...Would you have a spare or know where I can get one fairly cheap ...?

In the US you could try someone like Voluparts.com in Atlanta 404-352-3402

as noted, the resistor is only in play at the lower speeds so a fast test for a failed ballast resistor is when the fan works with the selector set to max and not at the lower speeds. Check out IPDUSA or FCP Euro for parts. FWIW, it looks like the ECC resistor is about $150, the manual version is way less!

would that be the dreaded " Thermistor " ? Why would it reset itself after key is cycled on/off and blow at any speed until it quits again ...I think Im gonna try a remote ground on resistor black wire ! ?