Hi everyone, newbie here. I recently purchased a 1994 850 turbo wagon and I'm having a problem with the climate control. The fan runs constantly but I have no control through the dash. It also does not light up at night with the other dash lights except for the flashing REC & AC lights. It seems to me that it might be the unit itself since it has no function at all. I searched the forum and did not find anyone that is having the exact same problem (some similar problems though). I would rather try to fix it myself than take it to the stealership. Can someone shed some light on this situation for me. Thanks in advance.

 

Man, there must be 50 post about this problem. Search a little more, read a little more, my guess would be that you need another control unit.

 

Thanks for the response. I guess I searched the forum but everything I found states that their unit works in some kind of way. My unit has not powered up or worked in any way since I've had it. I think it's the control unit too but I wanted ask some volvo people before I went ahead and replaced it. I have an Audi as well and I have replaced many things for no reason trying to fix a problem. Thanks again for the help.

 

Try Erie Volvo for a used replacement unit. 1-888-865-8613. I buy used parts there frequently, but in some case I get new cheaper at fcpgroton. That's what just happened with a catalytic converter I just bought and also the blower motor. I got both new from fcp cheaper than used from Erie.

 

I always hunt through salvage yards for parts as well.

 

Update - I replaced the control unit and now I do have control over the HVAC system. However, I still have the blinking A/C and RECIR lights. Do I need to get someone with an OBD1 tester to check it or can I do it myself? Thanks for all the help.

 

Ok, it stopped working again after I replaced the control unit.

I checked the codes and they are:
315 - Recirculation Damper Motor Shorted to ground or power
323 - Ventilation Damper Motor Active too long
325 - Recirculation Damper Motor Active too long
411 - Pass. Comp. Fan Overcurrent or seized fan
414 - Driver's side temp sensor intake fan seized

I guess my next step will be to check and clean the temp sensors behind the oh sh*t handles. Any other ideas would be appreciated. I would rather not take it to the stealership but I need my heat.

 

I checked the damper motors and the ones that i can reach work as intended. I was wondering if anyone knew if the headlight switch would have anything to do with my problem. The only reason I mention this is because when I turn the headlight switch on my blower goes full blast through the defrost vents. When I turn the headlights off it shuts everything down. I also rechecked my codes after disconnecting the battery and now I am getting a lot (at least 20) of bad ground type of codes. After resetting I just get the code for faulty dtc code from ECC unit. The codes I had before are not showing up anymore. Thanks again for any help.

 

I don't know if it makes a difference or not but I bought a used ECC unit off of EBAY and it has yellow plugs in the back instead of green like my original one and my plugs. That unit worked perfect for a couple of days and then completely crapped out, no function at all. Now I put my original back in because it at least provides full blast heat to the defrost but also without any control. The original one also has no lights on even though I replaced the bulbs with new ones. Also the original only works on full blast when the headlights are turned on. When the headlight switch is off I get nothing. Thanks!