The everlasting HVAC problem

Post by **scot850** » 26 Sep 2017, 19:37

System needs this in place to operate, the blinking is because the system is not happy you removed it. From what you say it sounds like it is perhaps bad. Try to see if you can get one from a junkyard as they don't normally go bad.

Shame you are not nearer as I probably have a spare used one you can have. The part number should be #9145736, but over here they are about $100 CDN or so new from the dealer.

Neil.

dsno · Post by **dsno** » 30 Sep 2017, 16:02

yeah. i searced the net for a sensor. they are crazy money. i have no idea why a temperature sensor could cost this much..

ohwell. it is what it is. i'll have a look at a few local junkyards to see if there are any 1gen V/S70 cars there. or could the 850 have the same sensor?

which leads me to another thing, which don't have anything to do with my topic, but do the V/S70s share the door lock actuator assembly with the 850s?

winter and the freezing cold is soon coming, and my door key tumber will freeze. and i'm unable to use the key-fob (the fob woks, and the door locks and unlocks. but i cannot operate the door handle when the actuator has been actuated by the fob. works fine when using the key though..

Post by **sleddriver** » 30 Sep 2017, 19:25

dsno wrote: ↑26 Sep 2017, 13:35 soo. i've finally got to measure the "duct" temp sensor. its the one behind the glovebox? see attachment...however i cannot get this to corrolate with the chart that abscate posted....at ~18-20c i get about 12.8k ohm across the the prongs.

i even had it at 14.4ohms at one time..what gives? could this sensor be bad? the ECC didn't like being powered with the sensor disconnected. started to blink a steady red on the LEDs.

Put it in the freezer or refrig for 6 min. then measure the resistance. Next warm it up with a hair dryer and measure it again.

dsno · Post by **dsno** » 01 Oct 2017, 13:11

i could try that ofcourse

Post by **wizechatmgr** » 01 Oct 2017, 16:01

If the door tumbler is freezing, try something like ACF 50 to clean it out and gently lubricate it. Is it suffering from water intrusion?

dsno · Post by **dsno** » 05 Oct 2017, 08:21

since it freezes my guess is that it has seen some water.
however it would be better to get the actuator to work like it should

dsno · Post by **dsno** » 18 Feb 2018, 04:21

sooo.. 4 months gone and nothing has changed.. . i'm still freezing my ass of.

have a new heater fan on order as the stock one from 1999 suddenly started oscillating, then completly stop working. .

a nudge with a stick on the fan motor and it jumps into life again for a short while

however. air coming out of vents are still cold.

the blend door actators all seem to work, with no ill sounds. the blend doors themself are freely moving. the heatercore is warm (not as hot as i would like it, but it gets hot). heatercore was replaced a few weeks ago as i noticed a tiny tiny drip from the OEM one (which was volvo original from 1999).

thermostat is new, this too was dated 1999 and was original. the old coolant smelled so bad i almost womited. i don't think it has ever been replaced before. it was opake with a greenish tint to it. but its all new now

so. all this rambling set aside. what i'm really fishing for here are some more tips

can the blend doors get out of sync? and is there a way to resync them yourself?
can the blend doors "foam" disintegrate leaving a ton of blow-by? (i don't think this is the case. as the air is moved around correcly when selected on the ECC, and i cannot find any traces of foam in the vent tubes)

are these common faults?

engine reaches operating temperature, and i'm freezing inside the car. thats no good. and i can't seem to find the solution either :/

help me save this old V70 D5252T from the wrecking yard. because it will end there if i can't get more heat out of it

dsno · Post by **dsno** » 18 Feb 2018, 06:34

soo. did some more research today..

heatercore inlet is at 81c and outlet is 76c.

however. the temp out of the vents are only about 50degress c... thats not very hot at all. should be closeer to the heatercore temperature.. hmm.

is there a blend door i don't know about here?

to my knowledge there is 4 servomotors.

driver heat
passenger heat
resirc flapper thingy (which often falls of the servo shaft)
floor heat.

am i missing something?

Post by **abscate** » 18 Feb 2018, 19:39

There are two blend motors and one direction damper, but early 99 cars have two directional dampers

It sounds like either both your blend motors are bad or the control unit is bad

dsno · Post by **dsno** » 19 Feb 2018, 10:00

the two blend motors are those heat/cold for passenger/driver?

bot those seem to work, as i get AC cool air when i turn the temperature down.
the directional motor (atleast for the floor) works just great.

i've had the driverside heat/cold blend motor of and inspected it inside. looks great. the plastic cog-wheels are in good shape and the carbon tracks almost shows no wear. i did clean of some lithium grease from the carbon tracks tho.

the blend door this motor controlls is easy to move. and the motor works just fine when i adjust the temperature.

i have been thinking it MIGHT be a problem with the ECC control unit, but it does control the servos.

The everlasting HVAC problem

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