94' Volvo 855T no air comes out the vents (ECC)

[henrysin44]

This happened one day, turned the fan on max, blower comes on but only the slightest amount of air comes out of the vents, just enough to take forever to heat the cabin. The center dial does nothing and only sometimes can i hear a vent move when turning it. I checked the blink codes and every motor is 'runnig too long'. Also some times the blower motor doesn't come on unless i restart the car. Anyone experience something similar? Seems odd one day every motor would quit.

[jreed]

It sounds like you can hear that the fan is turning at full speed, but you're not getting any airflow. Is that right?
Some guesses for things to check/consider:
Could it be that the white plastic recirculation arm has popped off of the damper shaft?
Did you try reseting the error codes in the ECC and then seeing which ones return?

[scot850]

If the inlet air flap is jammed closed this would give this issue. Could be the small servo motor is bad and not opening. For the moment I can't think but if the flap plastic actuator arm is broken, I thought it leaves the flap in the open position? Reason for thinking this is having owned a few, I have found the arm broken on several cars and not had any air issues.

I'd suggest removing the glove box and check if the arm on the inlet flap is working. If you set the ECC to re-circ the flap should close. If it is closed in any other position then the motor is bad.

Neil.

[Sommerfeldt]

This doesn’t seem entirely accurate. Even if the REC is engaged, there should still be airflow controllable by the fan. I’d suggest checking the flaps, of course, but also check that the inlet under the cowl isn’t clogged, and that the filter (if there is one) isn’t clogged or soaked with water, for example.

- S

[henrysin44]

Ill take a look at the cabin air filter and REC actuator arm, hopefully its one of those, trying to avoid having to remove the dashboard. Oh forgot to mention but if I open the air-mix air comes out of the center vents full blast.

[scot850]

When you have the glovebox out to check the air intake, also check the drive motor on the RHS of the center column behind the radio area. The 850's have a habit of breaking/splitting the connection between the motor (a square section plastic sleeve) so although the motor turns the flap inside the heater box does not turn. Often this can be repaired with a zip-tie around the cracked sleeve pulled tight. You used to be able to buy the part but I'm sure it must be N/A by now but worth checking.

Check the database as I used that as a giude many years ago with our 93 850 GLT.

Neil.

[scot850]

Should have added. When working on the system, it is always worth cleaning the 2 small cabin air temp sensors. They are hidden behind the grab-handle above each front door. These build up with crap in the air over time and they have a little fan to pull the cabin air over the temp sensor and this gets clogged and cannot adjust the temp.

Neil.

[Klausc]

Clear the ECC codes before you do anything. I cannot envision all vent flap motors dying.

I had an 850 where the owner tried to 'reset' the flap positions, 9-9-9 exercise, but failed. This caused the center stack flaps to get stuck in the closed position. I had to remove the dash to get it all working again. Fortunately it was Spring and not cold weather.

Usually, the 'slow to respond' will show up in cold weather when the ECC is left in manual mode rather than Auto. The vents need to be actuated by rotating vent the dial very slowly (10 seconds in each position) several times. Same for the recirc switch.

[henrysin44]

Clear the ECC codes before you do anything. I cannot envision all vent flap motors dying.

I had an 850 where the owner tried to 'reset' the flap positions, 9-9-9 exercise, but failed. This caused the center stack flaps to get stuck in the closed position. I had to remove the dash to get it all working again. Fortunately it was Spring and not cold weather.

Usually, the 'slow to respond' will show up in cold weather when the ECC is left in manual mode rather than Auto. The vents need to be actuated by rotating vent the dial very slowly (10 seconds in each position) several times. Same for the recirc switch.

I'll give that a try, I read the codes and from what I remember almost every motor had "slow respond" or "short to ground / V+" I've never had the ECC in auto mode before, I just set the speed and vents. Currently, as it has been sense October last year, all air is only coming out of the center vents, passenger vent (by airbag), and the vents where the dash meets the windshield (defrost vents im guessing). Although temperature control is fully functional, it adjusts just fine in heat and A/C thankfully.

I'm pretty sure i'm looking at a dashboard removal and 'new' motors for the system.