Chevrolet Repair: 91 Chevy Blazer Heat, chevy blazer, resistor pack

Question
91 Chevy Blazer S-10/Tahoe
The heater fan stopped working completely. Also the dash lights for only the heater are out.  
All fuses were checked and changed.

Prior to heater not working....
The fan would only work on "high" for about 3 days.

Recent work, over a month ago:
The steering column was tightened/re-seated.
New exhaust system and oil change.

Thank you in advance.

Answer
Hi Nic,
The control module for the heater comes to mind.
The resistor pack would explain no speeds except hi, but it wouldn't effect the lights and controls.
Try removing it,(the module), and then just reconnecting it.
I would also check the fuses again, and see if there is a blown fusible link.

Van