The ECC has temperature numbers on the dials and a variable speed setting. The blinking lights of death mean that there is a error 'somewhere'.

It is possible that the vent damper has a broken piece of plastic on it, allowing the damper motor to spin too far (error). It is repairable, but don't expect a Volvo garage to fix it for you - they don't know how. And they charge by the hour.

You will have to take off the glove box and kick panels and look around for yourself. It is a pain.
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Keeping it running is better than buying new