Have a 40th Annv (93) the heater fan stayed on after shuting down ignition. All efforts to shut it down failed. Finally disconnected it to get battery charged. Is this a replace the whole controller issue or can it be fixed?? JDR
Problem was fan control module, very common problem on GM vehicles. $69 from Ebay.

That problem USUALLY means the blower control module has gone bad. It's located on top of the AC/heater box-under hood -right side -top of the box. JMO

Thanks, that was it cost $77 from ebay delivered. Dropped it in and it,s fixed. Seems to be a common problem on GMs. Thanks again! JDR