We have had problems with the AC/heater in this 850 since we got it. It worked great when we got the car and a week later wouldn't work... off and on it would randomly work fine, heat and cool air. It completely stopped working when it got warm out in the summer so I tried getting into all the relays and cleaning them off and reconnecting them. I guess it worked because it worked for a few weeks then one day when Tiff was driving home the fan was stuck on, on the highest setting. Even if the car is turned off and the key is out of the ignition it blows as powerfull as you can imagine. We had to pull the fuse to stop and and to this day (several months) it still does it if you put the fuse in.

Where should we start looking for reasons the fan blower speed control thingie is stuck? Only removing the fuse or battery will stop it.

-Robb

 

Does the car have the manual climate control or Electronic?

 

I think electronic.... it has an auto setting but pretty much nothing works for any setting... I remember reading something about cleaning the sensors or little fans for the sensors above the doors where the handles are but I couldn't get anything apart without it probably breaking so I gave up.

What's the difference between manual and electric?? I know Mitsubishi's and this car is so complicated to me lol.

 

The power stage (often called the blower resistor) has shorted out. Was the fan making bad noises before this happened?

If the fan was screeching before fix that at the same time since that is what kills the power stage.

Remove the fuse (#5) to keep the battery from being killed - It sounds like you have already done that.

The power stage is inset into the blower duct just to the left of the blower motor as you look at it from the passenger's side footwell.

They are pricey little buggers.

...Lee

 

Do I need to remove the dash or passenger side air bag to get to the power stage? I can goto the junk yard and try to pick one up for next to nothing so that's what i'll end up doing. It never made any noises ever... just randomly worked on and off.

are there any write ups on this?

 

The way I get to the power stage is to remove the glove box and the lower dash panel. I wound up working through the glove box but having the lower dash panel off helps to retrieve the screws that you drop and gives you additional light. On the last MCC unit I dealt with there was a wiring harness in the way that partially blocked the T-25 Torx head screw and I wound up using a T-20 bit, cocked at an angle and with gentle force, to remove and replace the screw.

If you need to remove the blower motor itself you need to remove the knee bolster behind the lower dash panel as well. It has a bunch of SRS warning stickers on it but it has no impact on the SRS system when you remove and replace it.

...Lee