1993 Volvo 850 blower motor resistor location

[hostsb]

Hello
I Posted in the wrong Place before but still need help. Fan Runs all the time so I replaced The Blower Resistor and still blows high all the time even when the key is off. Pulled fuse 5 and the fan stops..... what else could this be...... even when the ecc is unpluged the fan runs on high all the time.....Please help.... Joe

[vjaneczko]

Joe, my ECC had the same “always on at full blast even when the key isn’t in the ignition” issue. The blower had burned itself out, and THAT blew out the MOSFET power state unit, so I bought a new one from FCP. Did you replace the resistor;


or the MOSFET power stage unit;



. . . which is the black device seen in Lee’s photo? You can only have one of them!

My understanding is that with the ECC setup, power goes from the battery, through the fuse, to the power stage unit, and directly to the fan. The ECC tells the MOSFET circuit how much juice to send to the fan. If the power stage has failed, it fails in the “open” position and it lets all the power through to the fan. So if that's the case, and you did indeed replace the power stage unit, you may have (another) bad unit on your hands.

[hostsb]

I just replaced the MOSFET power stage unit the lower picture........ if the fan blower is blown does that mean that I just blew the MOSFET power stage unit? That would suck

[MadeInJapan]

I know that this is an old thread but I just replaced my son's power pack on his 850. It was indeed the strange shaped unit on MCC (on his '94 850)- the one that is the upper picture here, that finally fixed the multi-speed blower. Now, if I could just figure out how to fix the heavy clicking when the blower is not on recirculate...

[BEJinFbk]

Broken flapper door where it attachs to the motor for the recirc flapper?

[clarkandrew45]

The blower motor resistor (or power stage in the case of the ECC) is inset into the air duct directly to the right of the relay(s) that are shown in MIJ's picture. With the ECC there is only the A/C relay, on the MCC there is the A/C relay and the max speed fan relay.

...Lee

Hello there mod, I just check on that one earlier, Thanks i find that resistor easily because of the pictures. Thanks for this, really a big help.

[elchopperfreak]

I believe the clicking is the mechanism that shuts the system so the air recirculates.
I just removed the blower and resistor and noticed in my car it was broken so it was zip tied in the shut position

[markyoung]

The blower motor resistor (or power stage in the case of the ECC) is inset into the air duct directly to the right of the relay(s) that are shown in MIJ's picture. With the ECC there is only the A/C relay, on the MCC there is the A/C relay and the max speed fan relay.

...Lee

Hello there mod, I just check on that one earlier, Thanks i find that resistor easily because of the pictures. Thanks for this, really a big help.

I agree with you for this one mate. That picture also helps me alot, i easily found that thing on when i have checked on that last night.

[Hamfisted]

If you are blowing the thermal fuse in the power pack control module try pulling the fuse and letting it reset. The fuse will reset, but the main cause of the thermal fuse blowing is high load in the circuit and this is usually caused by warn out blower motor brushes. The brushes wear down to zero rather quickly (50-60k miles on the car...), so don't be surprised when you start having blower problems. If you are going to the trouble of replacing the power control module, take a look at the blower motor itself. Pull it out of the duct housing, remove the motor from it's shroud and inspect the motor brushes. A new Bosch motor is only about $75 from FCPGroton and well worth it. They're cheap but don't last long, nothing you can do about it. Good luck.