I just purchased an '83 4wd long bed and am loving it however the A/C doesn't blow very hard at all. It gets cold just fine but there isn't much flow out of any of the vents. I found a little knob next to the connector on the heater/ac box that adjusts the blower speed but there isn't much of a noticable difference between the lowest setting and the highest. I have never owned a vehicle with this type of secondary fan speed control and was wondering if anyone has had this situation and also if it is normal. I suspect the module the little knob attaches to is faulty and causing my issue but don't want to blindly throwing money at a problem by guessing.

 

I,m not sure on what little black knob your reffering to for adjusting the fan speed, if its the black box under the dash on the side of the ac/heater unit then thats the idle stabilizer amplifier and has nothing to do with fan speed, it adjusts the cut out speed of the compressor at idle.
Does the heater fan blow OK without the AC on? does it have all the speeds working? as the AC uses the same fan motor as the heater, only difference was originally when they added the AC at the dealer the fan motor was replaced with a higher output fan and a different blower resistor.
If the fan deal checks out you might have a diverter door not open or closed properly in the ducting thats restricting the air flow out the vents.

 

Thanks for the info, it doesn't matter if the ac is on or off the fan is the same. The switch works and the fan speed changes for each position so I'll take a look at the ducts and flaps. I have seen fan problems in other makes caused by the resistor so I may replace that first and see

 

yeah check the resistor, its known for going out but when it does you dont have any fan at all at the certain speed that is selected...maybe the fan motor idk..GL

 

It's probably the blower switch knob that you are talking about. I remember my cousin also having issues about it where it doesn't work properly so he had no choice but to replace it. You also might want to check the resistor like joey mentioned as they are prone to go out and fail.