1999 s70 awd no heat [low coolant] 9144221 [map of ECC damper positions] Topic is solved

Post by **abscate** » 30 Jan 2026, 19:02

Finally broke the s70 out of the ice , started up, and no lights on the ECC control unit

Came on after a few minutes, then no heat

Blower fine, looks like damper isn’t selecting heat path.

Possible damper motor broken
Door stuck?
ECC electronics ?

Blend door
Volvo HVAC Heater Blend Door Actuator - Genuine Volvo 9134729

Post by **abscate** » 31 Jan 2026, 14:13

Well , Itwarmed up to 21F so thought I would run through the CCN diagnostics. Dampers are working , so either the flaps are stuck or something else.

Hood is frozen shut but coolant light is off

Temperature gauge normal.

Damper vs knob data

…and I solved the problem.

It was cheap, $25 retail but free to me

Any guesses?

Hint. The prudent mariner mechanic never relies on a single source of information for navigation diagnosis

Dub24 · Post by **Dub24** » 31 Jan 2026, 14:26

Are the windows fogged up ?
Check the front carpets nearest the center console for damp / wetness
The reason I'm asking is it could be the heater core
If it is don't worry it's easily replacable from under the dash. No need to remove the dash like other cars

Post by **abscate** » 31 Jan 2026, 15:31

Dub24 wrote: ↑31 Jan 2026, 14:26 Are the windows fogged up ?
Check the front carpets nearest the center console for damp / wetness
The reason I'm asking is it could be the heater core
If it is don't worry it's easily replacable from under the dash. No need to remove the dash like other cars

No , but full credit given. Got hood up and she took almost a gallon of coolant. Not sure where it is leaking but heater core is prime suspect. I better get that light fixed

Post by **scot850** » 01 Feb 2026, 00:27

No low level warning light? Had it stuck in the header tank?

Neil.

Post by **abscate** » 01 Feb 2026, 01:54

scot850 wrote: ↑01 Feb 2026, 00:27 No low level warning light? Had it stuck in the header tank?

Neil.

I will check bulb and circuit in warmer weather. I think this car seeps at the radiator and I blew coolant at idle while I shoveled driveway. Glad I didn’t hurt anything. Good lesson there.

Post by **abscate** » 11 Feb 2026, 22:18

Topped it off and ran 3 miles into town. Reservoir empty

:O

I must have a gallon of coolant sloshing under floor so now it’s a spring project.

I will bypass the heater core later today when home to confirm core leaking

Ugh.

Rome to Torino to Milan, then fly home this am

Post by **volvolugnut** » 12 Feb 2026, 07:47

Opps.

volvolugnut

Post by **abscate** » 13 Feb 2026, 03:40

I really hope I haven’t torched this engine. On the plus side, no question I would redo the head if I warped it, it’s a beautiful 99,000 mile runner which Abby will take over when Evita dies….in 2036

Post by **abscate** » 13 Feb 2026, 14:35

Knocked off the heater core in 40F sunshine, 2 hours in drivewa

Bypassed core to confirm leak, used 5/8 hose for this

T15 screws rear each side. T25 screws in vertical position

T25cmachinecscrew on sealing block.

New orings

Juno Approved!

Part number 9144221 FCP ORDER R671910733