I have a 2006 Ford Mustang v6 4.0 the ac will not turn on. I have checked my fuses they are good and I’ve checked my blower motor it works .Also I replaced my blower motor resistor with one from a 2009 mustang and it still will not turn on. I think it might be the plugs that control the speed and where the air goes to because I while I was replacing the radio I seen that on the one where u control speed the wires are lose and as for the plug where u control where the air goes it was hard to move it up and down so I used a flat screw driver and the part that moves up and down to take off the plug snapped in half PLEASE HELP!!
First you have posted in the 1996-2004 model year section. But I'm good with electrical and do have diagrams for your model year.
The inside blower motor is grounded via the blower motor resister AND the blower speed control. IF this were my car I would GROUND OG-BK wire at the blower motor resister. This should cause the blower motor to run on high. If this restores AC function this means we are going in the correct trouble shooting direction.
At the end of the day IMO you are going to have to fix the broken plug unless you are happy running the blower on high all the time.
Try searching car-part.com for salvage yards in your area. This might be a good source for a new AC/heater dash head control unit.