ECC climate control temp sensor measurements made easier

[jlaakkonen]

I've been testing all kinds of things now. I took apart the whole dash cuz I had to fix the odometer. While I was at it;

I opened up all the damper motors and cleaned them from the grease, and tested them all witha a 9v battery; they all worked.

I also opened up the ECC unit again, and actually found a small crack in one of the solderings in the circuit board that is behind the passenger side temperature selector(this was one of the error codes). Resoldered that.

Tried to test the grey/green wire from instrument cluster to ECC unit, but wasn't quite sure how to do that(the code was 1-3-5 no engine temp frequency signal and my engine temp gauge does work).

Cleaned the driver side temperature sensor fan, which had siezed. Also tested it afterwards with a 9v battery, and it does work.

Afterwards when I was the testing the ECC unit with my homemade apparatus(still has the same problems) started to question a few things:

1) Does it matter in what position all the knobs are in while testing? AUT? how about REC? and AC?

2) My homemade testing device has 10kohms resistor and not 5kohms; does that matter? Shouldnt it just affect the brightness of my led?

[jreed]

Interesting findings!
As far as I have heard and read, it doesn't matter which position the knobs and switches are turned to when you read the codes.
I don't know what effect the higher resistance would have on the code reader, except that if it is too high the LED will not emit enough light to read the codes. If you can read the codes and erase them with the 10kOhm value, it is fine. I used 5kOhms because the LED was bright enough to read in daylight and I figured that the lower the current the better as long as I could see the light. Others have used a resistance value around 500 Ohms and that seems to work well too. As you point out the higher the resistance, the dimmer the LED will glow.

Another good thread on home-made code readers (I can't find the resistance he used for his red LED):
https://www.matthewsvolvosite.com/forums ... 37&t=60660

[mecheng]

Excellent thread, one important point. You must read
All the codes first before clearing the codes, it won’t work
Otherwise.

Good chance you have lots of lint on your temp sensors
They are locked near the grab bars on the ceiling On the 850 not on the dash like the s70
My fan was spinning okay but the temp sensor was dirty.
After I cleaned them all is well and no blinky blinky!

Here is a good video;

[wyoben]

Howdy all,I hope I'm not too late to this topic to receive a reply ? I have a 94 85 Turbo wagon w/ the climate control ? heating system . Someone had gutted the dash in it , and I am in the process of replacing it . my question for now is , where do the inside Temp sensors ? go . Hope I havent been too ambiguous in my wording . and thanks to all at Mathews Volvo site for the help! p.S. I love my Volvo's I only have 5 wagons

[abscate]

On the 850s the temp sensor are up in the headliner above the doors, it moved to the dash inthe V70 series.

[wyoben]

Really ! okay thank you, I will see if I can see where the butcher pulled them out .

[wyoben]

Let me ask you one more question , if a guy was gonna look for a V70 R, what year would you think is the best ? I hope I don't offend anyone by not putting this in the right category .And thanks AGAIN for the help

[misha]

Ecc unit will clear the codes itself once the problem is solved....just like abs unit.

I had a seized temperature sensor/fan on passenger's side roof...replaced it and no more flashing ac/rec lights.

[wyoben]

Hope I'm not interrupting here Guys , my apologies if I am , Abscate I'm posting a few pix of my heater control unit , and the 2 sensors , for the life of me, I thought they went in the ducting nearby ...their electrical leads do not look long enough to go in the head liner.Am I wrong on that ? Thanks Ben

[abscate]

That wiring looks butchered, are you sure it’s stock? I don’t know that year very well at that level of detail.

Answering other thread above...

Let’s see, 1999 passed all the other yeaRs , and pRince wRote a song about it.

No one likes 2000 because it thinks it’s the last year of the Millenium, and 2001 begins the Space Oddity of P2 and Major Tom Foolery, and poor Ground Control.