[Grim Reaper]

The Fat red wire is high only. If you have no speeds it's a control issue. On the side of the box is another set of wires into a plug. that's you low speed blower resistors. Just so you know.

Even in the off posisiton the fan should run in a very low speed. If it's not then it control and possibly a issue with the ignition switch. Check the plug on the colum and make sure it didn't get kicked. It's on the top of the colum about midway between the dash and floor.

Done anything under the dash recently? Anything else not working?

Check all the fuses. I dont have my truck here today but I think one is marked HVAC or Blower. I'd have to look again but I seem to recall the A/C trucks had a fusable link under the hood. It's either tied into that block on the fire wall hanging down betwwn the brake booster and engine or it's down at the starter.