'95 850 ECC system stopped working

andrewmudd · Post by **andrewmudd** » 24 Nov 2009, 14:32

I've had the car about a year and, to this point, the ECC system has been working fine. Without warning, about a week ago, the recirc and A/C lights started flashing for 20 seconds when I start the car and it stops blowing any air at all.

I've pulled the codes from port B1 (and looked up their meanings), and I've got the following:

141: Faulty signal from driver’s side temperature selector switch
325: Recirculation damper motor active too long
411: Blower fan seized or drawing excessive current
414: Driver’s side interior temperature sensor inlet fan seized
417: Passenger’s side interior temperature inlet fan seized
418: No control signal to blower fan power stage

So what's the verdict? What's the best way to go about making the climate control system work again? Unfortunately, a $1,000 repair bill isn't an option for me right now, so is it something I can do myself, or should I just resign myself to not having heat or A/C in the thing anymore?

Thanks in advance for any help at all!

Post by **Ozark Lee** » 24 Nov 2009, 17:53

Welcome to MVS,

From the codes and the symptoms the blower may have fried and it may have taken the power stage (blower resistor) out with it.

For starters check fuses 5 and 31.

The test for the blower is to ground the blue wire that goes to the blower (you can do that through the back of the connector) and see if the blower runs full blast and runs smoothly. If it does then the power stage is bad. If the blower does not run or it is noisy then it is likely bad and the power stage may or may not be bad. I know of no test other than "replace with known good" to for sure diagnose the power stage. It is a pricey part and it is non returnable. The other codes are the fans in the temp sensors which are located above your grab bars. That is a very common problem but it won't keep the system from working. The temp sensor fans can usually be cleaned up, hit with a shot of oil, and they will work fine again.

...Lee

Post by **outdoor7or24** » 03 Jan 2010, 13:08

Ozark Lee wrote: The other codes are the fans in the temp sensors which are located above your grab bars. That is a very common problem but it won't keep the system from working. The temp sensor fans can usually be cleaned up, hit with a shot of oil, and they will work fine again.

...Lee

Lee, I am sorry but when you mean the grab bars are you talking about the oh crap handles?
Just pull the plastic off and they will be there?

thx as I got B1 codes 414 and 417

Post by **Ozark Lee** » 03 Jan 2010, 13:43

I have never had to remove mine. I only have one car with the ECC, the others are manual, so I can give you no real hands on tips from experience. It is my understanding that you need to remove the grab bars which is done by flipping open the cover plate on both ends of the handle. From there I think you can just pop the cover off of the sensor assembly and clean up and lubricate the fans.

I know there is a writeup floating around somewhere but I can't seem to find it to give you a link.

...Lee

Post by **outdoor7or24** » 03 Jan 2010, 20:44

https://www.matthewsvolvosite.com/forums ... 27&start=0

MIJ says they are at the grab handles.
"The temp sensor/fan motors above the doors are very easy. Click down the tabs on the grab handles to reveal the screws. Undo these and take the grab handles off, then you'll be able to see what's going on. The sensor/motor has a connector that you can take it loose from and then the entire contraption can come out for cleaning, lubing etc. That's all it might require."

I do not recall seeing them when replacing my headliner.....

gdict · Post by **gdict** » 15 Oct 2012, 13:11

Lee,

I hope you monitor these old threads.

I was helping a friend with her 95 854T ECC issues. Her fan was not working and she was getting the flashing lights. Unfortunately I don't have the codes, but the biggest issue was she kept having a dead battery and was needing jump starts. Battery tested ok, 13.8V at idle, so alt is good. I started pulling fuses and check for current and got 3.8Amps on Fuse 5 with the car off. I pulled the glove box and knee bolster (after having to break into glove box due to bad latch) and pulled the fan. Fan tested ok and the current draw went away with all the connectors disconnected. I put the fan back and reconnected everything. 3.8amps again. I pulled the connectors one by one and found that it was what appears to be the main power supply for the ECC system. With this disconnected I got no lights on the ECC and the current was gone at fuse 5. This is where it currently sits and the car starts fine with no dead battery.

You spoke of the "power section" to the fan. Is the resistor unit? Could this cause the 3.8amp draw on fuse 5? I have an ECC out of scrapped 96 850, but I don't think I have the resistor pack. I don't want to throw parts at the problem, so I was hoping to get your opinion based on the information I have described.

Thanks,

Greg

Post by **Ozark Lee** » 15 Oct 2012, 16:55

Based on your description, I think you have both a seized blower and likely a bad power stage (blower resistor). The "blower resistor" on an electronic climate unit isn't a resistor at all, it is a MOSFET transistor. A seized blower motor will often cause the power stage to fail due to it drawing too much current. A bad power stage, on the other hand, won't necessarily cause the blower motor itself to fail.

You can test the blower motor by shorting the black wire and the blue wire on the blower power plug at the power stage. When shorted, the blower should operate at full speed with no squeaks or bearing noises. You can do this in the key off position as one of the "features" of the blower motor is that it is always hot.

If the blower motor passes the test then you are looking at replacing the power stage. The power stage is inset into the top of the main air duct just to the left of the blower motor as you look at it from the seat. If the blower motor fails the test then you are looking at at least replacing the motor and perhaps the power stage.

You want to avoid plugging a new power stage in with a bad motor as you can blow up the new part.

...Lee

Post by **BEJinFbk** » 15 Oct 2012, 19:23

It seems odd that you would see all those failures at once.
I'm placing my bet on low voltage or a toasted ECC module.

gdict · Post by **gdict** » 16 Oct 2012, 11:44

Thanks Lee.

The motor tested good. I had it completely out thinking it was bad and it ran fine with no noise when connected to 12V. I will double check with the short method before I put in a new power stage.

Cheers!

Greg

Post by **cn90** » 16 Oct 2012, 12:02

At least pull the resistor to check.

The transistor original PN is 2SK1423.
You can use STP140NF55......couple bucks at digikey dot com.

Have a look at this DIY replacing only the MOSFET (Make sure you scroll through all the pages of the thread below):
http://www.volvo4life.es/foros/bricos-v ... 1-a-4.html