Slowly failing climate control unit Topic is solved

nsomlai · Post by **nsomlai** » 10 Nov 2016, 03:47

My 2000 S40's climate control unit has been failing for over 5 years now. It takes longer and longer to set the proper air temperature blown into the cabin. Now it takes 30 minutes so I asked the official garage for a diagnosis and they confirmed that the signal does not get to the servo of the air mixing valve. I also made the mistake of asking the price of a replacement (US$ 1000), still recovering from the shock.

My guess is that there is a loose electrical connection (soldering or cable) somewhere and the warmth of the engine makes it better. Do I stand a chance trying to find that?

My other option is to buy a used one. Is it easy to pick the right one on Ebay just by photo? Or are there identically looking modules with incompatible electronics? Or if the buttons and knobs match, it will be good for me? How about ones with Fahrenheit scales but otherwise identical? I found a few of those.

difflock54 · Post by **difflock54** » 10 Nov 2016, 16:24

I read on another volvo forum just today that problems with the climate control unit can sometimes be sorted out by a cleanup of the contacts with an electrical contact spray. Might be worth a try?
Using a 2nd hand unit with fahrenheit calibrated knob should work fine as the unit itself will not be different.

nsomlai · Post by **nsomlai** » 10 Nov 2016, 23:07

Thanks, I obtained an old Vadis copy and the part number for Fahrenheit and Celsius is the same. Unfortunately there are more modules available on Ebay with no seat heating and DSA, this full-fledged version seems to be more rare. (Although I don't remember ever using the DSA off switch in 16 years.)

Yes, the service guy agreed that it may be a loose connector or soldering point that works better after the cabin gets warm. I'm considering taking it out and try my luck with contact spray and re-soldering suspicious points. The problem is that winter is coming and if I ruined it completely and couldn't find a new one quickly, I would need to get around without heating.

cbburtraw · Post by **cbburtraw** » 01 Dec 2016, 16:59

These units are pretty unique to the old 40 series. I doubt you'd mix em up with another model.

I'd definitely check the connectors. Maybe hold of on taking the unit itself apart until spring if you're worried about losing it.

Mine seems to not work here and there... full heat or no heat sometimes. Not often enough to warrant tearing it up just yet though - thankful for heated seats. Let me know what you do if you fix it.

nsomlai · Post by **nsomlai** » 27 Apr 2017, 00:59

Things continued to get worse (fan speed control also started to work interemittently) so I ordered a used unit off ebay. I planned to install it myself, but then I read about damper motor calibration. This is a used ECC so I guess automatic calibration will not work, it should be initiated manually from VIDA. And I don't have the software.

Will it do any damage if I use the unit without calibration until I get to a repair shop next time?

nsomlai · Post by **nsomlai** » 02 May 2017, 13:41

Replaced the unit. The new one works OK. Will pop into the local shop for calibration tomorrow.