Its about to get cold here so this is a matter of vital importance. I dont feel liek roasting to death every time I cut the heat on so im assuming somehting may be wrong with my controls. I have the electronic HVAC controls and when I turn them to, lets say 78 degrees it still feels cold. If i turn off teh A/C the temp gets a little warmer but nothign like 78 is supposed to feel like.

If i turn it to the 12 oclock position then it gets hot. REALLY hot. Thats al well and good but I'm thinking it should get warm before I have to turn it to max heat.

What wrong with my baby?
Help

 

When you first start the engine, do you see the "REC" and "A/C" LEDs blinking? If so, there is a problem in the ECU. If not, the ventilation/damper motors may need calibration. You can either buy a Haynes manual and play with it, or give up some $ for a dealer or independent shops that specialise in Swedish/European cars.

Unfortunately, you would have to go to the dealer to retrieve codes from the ECU, as your 850 is '96. '93-'95 models came with a terminal where you could access the ECU manually.


JPN

 

this thing is strange. I saw teh lights blink only once and that was a month ago. I drove around for a few lastngiht and the heat worked around the 74 range. Guess its tempermetntal

 

Might be the switch itself, ratchet the switch through the range or look into replacing the unit with a yard unit?

 

Since it is a climate control system it may be that the temp inside the car is indeed higher than 78. If thats the case it will blow cold. As far as I can tell in my 850 the only way to demand hot or cold regardless of the interior temp is to turn it all the way hot or cold. Otherwise you will just get whatever needs to be done to meet the temp you have selected. Just the other day it was cold enough out that when I had the temp set at 72 I actually got heat, I was shocked as I never saw any heat before out the vent except when cranked all the way to hot.

 

Electronically controlled systems usually have an internal temperature sensor somewhere. I still havent found any info stating where it is located and how/when to replace it.

What ECU needs to be replaced? The ECC or the car's computer???

 

Clean the sensors... I think I read something about on the dash? Compressed air/vacuum/isopropyl alcohol gently... =) a clean car is a happy car... smokers probably have this worse... then again so do their lungs, ji ji ji.

 

I dont smoke and I had the car detailed today. Still not sure where the sensor is at...

 

There are several temp-sensing sensors in the 850; see attached.

If you are not getting warm air, is your engine temp at 3 O'clock plus minus? If the engine temp does not rise, I would replace the thermostat (easy job with a service manual, a few hand tools, OEM parts & safety).

1996 & 1997 850s require diagnostic equipment. With wild guess, I can only assume the following:

- Damper motor out of calibration/not functioning.
- Duct temp sensor reading out of range.
- ECU needs to be replaced (try a junkyard first)


JPN

 

set a thermometer inside your car, and see what the interior temperature actually is. If it's above 78 degrees, then you WILL only get heat if you turn it to the end of the dial, which makes the system ignore the temp sensors. That certainly explains why you got heat at a lower setting at night, when it was cooler outside.

 

The cabin temp sensor in an 850 is behind the drivers grab handle in the roof. When the fan behind the sensor clogs with dust and stops turning you no longer have airflow across the sensor. The P2 cars have this problem A LOT. Usual sypmtom is that you always have A/C until max heat is selected because the sensor is not only shaded but insulated from the warm cabin air by all the lint.

 

i took them out blew them out with compressed air then reinstalled. no fix. I then got another set from a bone yard. same thing.

Pulling the codes today

 

hooked up the computer @ advance auto today and it said "NO CODES FOUND".

Lame.

Sometimes it flashes lights at me so I guess i'll try counting those and report back.

 

OBD-II code readers (like what they have at Advance or AZ) ONLY read powertrain codes. The flashing lights on the climate control ONLY mean that there IS a problem, they don't flash a code. Unfortunately, the only way to get climate control codes pulled is to go to the dealer or a shop that has a scanner that can do full functions on a Volvo. There's no other way to get those codes. Your climate control MIGHT just need re- calibrated. The dealer can do that for you, as well.