Heater blower fans always on

[freesaints]

In the process of diagnosing a sound from the passenger footwell, we discovered that the heater blower motor fan was binding on the squirrel cage. I've read through the forums and feel that I can try and clean this up to stop the sound. However, we found that the fan was always on when the car was running, even if the controls/fan was off. For now, we just disconnected it but does anyone know what would cause the fan to run all the time? Is this a relay issue or something else? I'd hate to keep this disconnected as I'll be wanting cabin heat here pretty soon.

[aj88cab]

The high speed setting (#3 for manual controls) for the Foot-well blowers runs through a round style relay at the front trunk relay panel. that relay is bad (stuck closed) and causing the FW blowers to run all the time. Replace that relay and you should be good to go.

[freesaints]

Great, thanks aj88. I'll give that a shot.

[aj88cab]

Just to follow-up. My previous reply assumed from reading your post that it was only the FW blowers running all the time, and that they were running at the high speed (#3).

If both the engine blower & FW blowers are running all the time, it could be the auxiliary cooling function temperature sensor gone bad. Located on top of the engine (triangle of death oil leak area). If you pull the connector (round single pin) from the temp sensor the fans would stop if this is the case. This requires replacement of the temp sensor.

And finally, if it is just the FW blowers at the slower speeds (0, 1, 2), it is possible the FW relay in the heater control relay module is fused, but this is less likely than the round relay mentioned above. This would require replacement of the pricey heater controller module.

These all apply if you have auto heat as well.

[Hotshot]

Apologies for not all colours match. I wasn’t super accurate when plotting paths. But the colours are listed.

[Hotshot]